Gender diversity and morphosyntax: An account of singular they

As one of the primary means of constructing gendered identities, language is a matter of central concern to transgender people (Zimman 2018). In this paper, we present an analysis of non-binary singular they; that is, they as used to refer to individuals whose gender identity is not, or is not exclusively, masculine or feminine. Despite singular they’s widespread usage and long history in English, not all speakers judge this most recent innovation to be grammatical, even if they do not object to singular they in quantified, generic, or otherwise gender non-specific contexts, and even if they produce the latter sort of examples natively. We argue that resistance to this new use of they can, at least in part, be attributed to speakers’ level of participation in a grammatical change in progress. Further, we propose that this change can be categorized into three distinct stages, with they’s most recent broadening – that is, as a non-binary singular pronoun of reference – dovetailing with wider socio-cultural changes (as well as featural changes beyond the pronominal system) that underscore the difficulty in separating grammatical and social judgements. As we aim to show, linguists from all subdisciplines – both theoretical and applied – are especially well suited to leverage theoretical insights to advocate for trans-affirming language practice.


Introduction
It has long been acknowledged by linguists, grammarians, and the public at large that English would benefit from an epicene pronoun (Armes 1884;Bodine 1975;Carlton 1979;Baron 1981; inter alia): a singular pronoun that could refer to known human individuals without having to specify a binary gender. 1 Currently, the leading contender for this role is they, as in (1).
(1) a. No professor i told me they i wouldn't be holding office hours this week. b. The right candidate i knows they i should bring a copy of their resumé. c. Every author i knows they i should get an early start in the morning.
They has a long history as a singular pronoun in English, and has occurred in constructions similar to (1) since the late 14 th century (Balhorn 2004: 91), used to refer to non-specific and quantified individuals. In recent years, singular they has expanded to yet another context: in addition to its long-standing usages, it is now also used to refer to specific individuals of known (but not necessarily binary) gender. They is not only an alternative to "generic" he and other more verbose but somewhat less sexist constructions such as he or she and s/he, but it is also the personal pronoun of reference 2 for many non-binary indi-viduals -those whose gender identity is not, or is not exclusively, masculine or feminine.
Yet not all speakers judge this innovation in the use of singular they to be grammatical, even if they would not object to singular they in sentences like (1) and would produce similar examples natively, as in (2).
(2) a. I don't recognize that. I don't recognize another person's i right to decide what words I'm going to use, especially when the words they i want me to use, first of all, are non-standard elements of the English language and they are constructs of a small coterie of ideologically motivated people. (CBC Radio 2016) b. Why would I discuss a person i that is not in my presence; and not know whether they i identify as he or she? (Facebook post, downloaded in 2017) In this paper, we argue that resistance to this new use of they can, at least in part, be attributed to speakers' level of participation in a grammatical change in progress. Further, we propose that this change can be divided into three distinct stages, with they's most recent broadening -that is, as a non-binary pronoun of reference -dovetailing with wider socio-cultural changes (as well as featural changes beyond the pronominal system) that underscore the difficulty in separating grammatical and social judgements. We show how this legitimate grammatical change can be accounted for in feature-geometric terms within a realizational approach to morphology (Distributed Morphology, Halle and Marantz 1993 et seq.). We also discuss what the account says about the English pronominal system -and the small set of English nouns that may also carry gender features -as a whole. Ultimately, we take the position that while this change may take time for some speakers, it is by no means insurmountable, and is either complete or well underway for an increasing number of individuals.

The social significance of pronouns
While a number of previous studies on singular they have focused on its generic or epicene use to refer to ostensibly binary-gendered individuals (Bodine 1975;Baranowski 2002;Balhorn 2004;LaScotte 2016;Bjorkman 2017; inter alia), few have centered the experiences or significance of pronoun usage for non-binary speakers specifically (though see Conrod 2018;Hernandez et al. 2018;Ackerman 2019). However, we contend that no analysis of pronouns and gender should proceed without due consideration of pronouns as forming the center of most discussions of (both binary and non-binary) transgender speakers' challenges to "the linguistic status quo" (Zimman 2016). Pronouns, along with proper names, are often among the first acts of linguistic selfdetermination a transgender person makes. In light of the significance of pronouns and pronoun recognition for transgender communities, it cannot be denied that grammatical judgements regarding singular they are inextricably connected to social judgements of these communities. Hernandez et al. (2018) found that speakers' judgements of singular they as grammatical (both as an epicene pronoun and as the pronoun of reference for transgender individuals) were significantly correlated to their scores on an attitude test: individuals with negative attitudes towards transgender people were less likely to judge singular they as acceptable. Attitudes towards transgender people were the highest predictor of the grammaticality of non-binary singular they, but the grammaticality of generic singular they was correlated both to attitudes to transgender people and to prescriptive attitudes more generally. Ackerman et al. (2018) likewise found a correlation frequently neither he nor she is acceptable at all. In such instances, the term pronoun of preference wrongly suggests that they is merely preferred over other alternatives. between familiarity with gender diversity and acceptance of singular they, particularly with prototypically gendered names and nouns such as Chloe and Jacob: as speakers' frequency of interaction with transgender and non-binary speakers increased, so too did their acceptance of singular they. Thus, there is ample reason to posit that in the case of singular they, social and linguistic change are acutely interconnected, perhaps even mutually constitutive.
As Conrod (2018) observes from a variationist sociolinguistic perspective, they is a change from above, i.e., a linguistic change in a speech community that is above the threshold of speakers' conscious awareness (Labov 1966). 3 As is typical for changes of this nature, speakers are aware of it and engage in discussion on its use and merits. And yet, this change is unusual in that, unlike many changes from above, it is not necessarily a prestigious one in the population at large. 4 Metalinguistic commentary on the use of singular they is mixed, as are the social consequences of (dis)aligning with it. In some communities (such as groups of younger speakers, LGBTQI2S+ 5 speakers, or anywhere gender diversity is recognized and supported), fluency in this feature may be valued; elsewhere, it may be stigmatized. As a matter of central concern for transgender speakers, the change towards non-binary singular they originates (at least in perception, if not necessarily in reality) from groups who have a high social salience, but not necessarily a high status (Conrod 2018).
Though recent public discourse might suggest otherwise, it should be acknowledged that even outside transgender communities, pronouns and pronoun systems are not unchanging or inflexible: pronouns are used in socially meaningful ways with great attention to the social context. 6 Therefore, we take no position on how singular they (or any other pronouns of English) ought to be used -rather, we seek to describe the pronoun system as it is already used by an increasing number of speakers, ourselves included. While describing the state of singular they necessarily involves taking into account the English pronominal system as a whole, it is singular they in its non-binary usage that is the primary focus of our analysis. Our questions at the outset, therefore, are: what does the pronoun system look like for speakers who already have non-binary singular they in their grammar, and how can a descriptive analysis of this system contribute to trans-affirming language advocacy?
Recently, Bjorkman (2017) presented an analysis of a relatively new variety of English, in which they can be used to refer to a singular definite individual of known gender, but where the distribution of singular they nonetheless exhibits some specific limitations not found in the variety we will report on. Both of these varieties expand the uses of so-called singular they beyond uses like (1), which, as previously noted, have been available since at least the fifteenth century. As Bjorkman (2017) is the first published account of the morphosyntax of definite singular they, we engage with her analysis in some detail. 3 Singular they is not the only change from above in the pronominal system in the history of English. For example, after the end of the Norman Conquest in England, the second-person thou (singular and by analogy with French, familiar) was lost in favour of the plural (and by analogy, formal) ye > you, due to the social risk involved in assuming power relationships between speakers during this time. 4 While the sociolinguistic literature often assumes that changes from above usually enter first through the speech of high-status groups such as upper-class speakers, who use these new linguistic forms to differentiate themselves from lower-status groups (who in turn may come to use the feature to sound more 'educated' or similar to high-status communities; Labov 2007), this is not necessarily always the case. As one reviewer helpfully points out, though non-binary singular they might not carry prestige in the wider English-speaking speech community, within communities that do use it, it is a highly valued feature. Within such communities, those who do not produce it may be urged to do so (sometimes via assertive correction). 5 Lesbian, Gay,Bisexual,Transgender,Queer,Intersex, A familiar example is the T/V distinction in Romance second-person pronouns, where the 'T form' is the pronoun of informal address and the 'V form' the pronoun of formal address, a general maxim that can be flouted or invoked in socially meaningful ways.
The innovative data Bjorkman discusses are exemplified in (3), where the antecedent of they is "singular, definite, and specific, referring to an individual whose binary gender is known to both speaker and hearer" (Bjorkman 2017: 2; judgements as reported there).
(3) a. %The professor i said they i cancelled the exam. b. %Our eldest child i broke their i leg. c. %I'll let my cousin i introduce themselves i . 7 Crucially, Bjorkman reports that while sentences like those in (3) are becoming commonplace, "even speakers who accept singular definite specific they as in (3) generally do not accept sentences like those in (4)" (Bjorkman 2017: 2, judgements as reported there).
In these examples, the antecedent remains singular, definite, and specific, but is now a proper given name or a gender-specific noun -though she does acknowledge in a footnote that "for at least some speakers, they is possible with given names if the referent is of unknown gender, or of known nonbinary gender" (2017: 2).
(4) a. *Janet i said they i cancelled the exam. b. *Thomas i broke their i leg. c. *I'll let my sister i /father i /aunt i / introduce themselves i .
In this paper, we report on an even more innovative variety of English, which represents the judgements of eight people we have consulted, 8 and which is also corroborated by the trends described by Conrod (2018). In this variety of English, singular they can be used to refer to definite, singular individuals of any gender (binary or non-binary), and can take antecedents like those in (4). In this context, we refer to the variety of singular they described by Bjorkman (2017) as Stage 2 of a grammatical change in progress, and the variety we report on as Stage 3. Stage 1 refers to the usage of singular they found in (1), which has long been well established in English. We begin by describing the most recent stage of the change: singular they in its nonbinary usage (Stage 3). We then turn, in Section 4, to our account of the three stages of singular they, showing how the progression from each stage to the next can happen. We also show how speakers can move directly from Stage 1 to Stage 3, and how, once speakers have made the move from Stage 1 to Stage 2, the transition to Stage 3 may be more difficult than it would have been from Stage 1. In Section 5, we compare our analysis to that of Bjorkman (2017), who deals only with what we call Stage 1 and Stage 2, and argue that her account cannot be straightforwardly extended to account for Stage 3 data. We conclude in Section 6 with some comments about the interplay between linguistic research and social responsibility, especially with respect to marginalized and stigmatized varieties and speakers.

The data at Stage 3
The speakers we consulted come from the extended networks of the first author, and include both self-identified non-binary speakers (N=5) and speakers who are binarygendered but have at least one non-binary family member (N=3). Though this is a small sample, it meets the SNAP criterion recommending a minimum N of 7 (Mahowald et al. 2016). Judgements were solicited via email. Consultants were presented with the sen-tences in (5)-(7) below, and asked to rate them on a scale of 1 to 3: a rating of 1 indicated that the sentence was fully grammatical and they would likely produce it themselves; a rating of 2 indicated that it was grammatical, but they would likely not produce it themselves (i.e., they might hear it in their daily life and interpret the coreference successfully, even if they would likely not use it); and a rating of 3 indicated that it was not grammatical, and they would not use it. All of the sentences were unanimously judged as completely acceptable by all speakers (i.e., all speakers provided a numeric value of 1), consistent with our own judgements. (5) Stage 1 singular they (quantified antecedent, or antecedent of unknown gender): a. Anyone i who thinks they i need more time should ask for an extension. b. The person i at the door left before I could see see who they i were.
(6) Stage 2 singular they (antecedent of known gender, but ungendered 9 description/name): a. Kelly i said they i were leaving early. b. The strongest student i will present their i paper next.
(7) Stage 3 singular they (antecedent of any gender, no restriction on description/name): a. Maria i wants to send their i students on the field trip. b. We heard from Arthur i that they i needed time to think about the idea. c. We asked [the first girl in line] i to introduce themself/themselves i . d. Your brother i called to say they i would be late.
It must be emphasized that when we say that all of the sentences in (5)-(7) are grammatical for our speakers, it is of course not the case that any one of them can be appropriately used in all contexts. For example, if the person named Kelly referred to in (6a) is an individual whose pronoun of reference is she/her, it would be inappropriate (but not ungrammatical) for a speaker who knows that about her to use they to refer to her. Equally, if the person referred to in (7a) is someone whose pronoun of reference is he/him/his, it would be inappropriate (but again, not ungrammatical) for a speaker who knows this to use either their or her when saying (7a). The well-formedness of the sentences in (5)-(7) thus means that the sentences can be used under appropriate circumstances. This contrasts with the judgments reported by Bjorkman, according to which sentences like those in (7) are ill-formed and cannot be used. For Stage 3 speakers, while they is always available as a singular, third-person pronoun, the singular pronouns he and she are also available, and when used as in (8), may -or may not -indicate that the referent is of binary gender. That is, while he and she may be used to refer to binary-gendered referents (i.e., a man or a woman, respectively), there are some non-binary speakers who also use these pronouns, or at least accept them. 10 (8) a. The professor i said he i wouldn't be giving us an exam. b. Kelly i said she i was leaving early.
For some Stage 3 speakers, he and she are ideally used only if the speaker knows specifically that the individual referred to uses those pronouns. Absent such knowledge, they is used, so as to avoid misgendering. Misgendering -in this case, using a pronoun that does not match the gender identity of the referent -has been shown to cause substantial psychological, social, and emotional harm (McLemore 2015), 11 and some speakers may therefore, consciously or unconsciously, avoid guessing or assuming an individual's pronoun of reference based on potentially irrelevant information, resorting to they as the least specified form.
For at least some of the speakers of Stage 3, singular they can also be used to refer to pets, as in (9), where in earlier stages of English he and she would have been used in lieu of it. However, truly inanimate objects, when singular, cannot be referred to with they, as in (10). 12 (9) a. Fluffy i didn't eat any of their i dry food this morning. b. Barkley i loves to chase squirrels, but they i never catch any.
(10) I put my favourite watch i down somewhere, and now I can't find ✓it/*them i .
Taken together, the judgements above represent Stage 3.

The morphosyntax of singular they: An account in three stages
In this section, we present our analysis of all three stages of singular they, showing that it provides a plausible explanation of the fact that some speakers seem to strongly resist the move from Stage 2 to Stage 3, while others make the move much more quickly. Specifically, we argue that at Stage 2, the pronoun system remains essentially unchanged from Stage 1; what has changed, for Stage 2 speakers, is the proportion of nouns and proper names that carry a contrastive gender feature. Gender features remain contrastive in the pronoun system, but as the number of gender-unspecified animate nouns increases, so does the distribution of singular they. At Stage 3, on the other hand, it is the pronoun system itself that has been restructured. The gender features at this stage are completely optional, leaving they as the default spellout for singular, animate referents. Stage 2 individuals who have accommodated to definite singular they by retaining contrastive gender features but revising the specifications of nouns and proper names still have a strongly contrastive, though vestigial, gender system in the pronouns. Moving from this grammar to Stage 3 requires exactly the same grammatical reorganization as does the move from Stage 1 to Stage 3 directly, but, as we will argue, the empirical evidence for such a move is significantly weaker for Stage 2 speakers than for Stage 1 speakers. As stated earlier, we adopt a realizational approach to morphology, in the tradition of Distributed Morphology (Halle & Marantz 1993 et seq.). In such a theory, pronouns consist of bundles of morphosyntactic features, which are phonologically spelled out in the post-syntax, in accordance with a version of the Elsewhere Principle (Kiparsky 1973). Syncretisms arise when a single phonological form, or Vocabulary Item, is the best fit for more than one featural representation, and the least-specified Vocabulary Item in a given category is generally referred to as the default form. 11 It should be noted, however, that using singular they to refer to a binary transgender person can also constitute misgendering; see, for example, the use of they to refer to transgender women to exclude them, linguistically and socially, from the category of women. As one reviewer points out, the avoidance of she in this case likely constitutes a particular kind of misgendering, specifically a form of exclusionary de-gendering or un-gendering. 12 We set aside here the fact that ships, and for some speakers other vehicles like trucks and cars, can be referred to with the pronoun she. We have no data on whether such entities can also be referred to with singular they, though we ourselves find sentences like (i) and (ii)  We also assume, for convenience and consistency with other relevant work, that the features of English pronouns are privative, and that they are arranged in dependency structures commonly known as feature geometries (Sagey 1990;Harley & Ritter 2002). 13 Finally, we assume that privative morphosyntactic features are generally contrastive. That is, in the absence of a feature [F] in a context where it could appear, the representation is interpreted as "not F"; that is, as not having the property denoted by [F]. 14 However, following Wiltschko (2008), we assume that in some cases, features are noncontrastive "adjuncts", which behave like modifiers. The presence of a non-contrastive feature [F] contributes the meaning of F to the representation, but the absence of such a feature in the context where it could appear has no consequences for the interpretation.

English pronouns at Stage 1
We assume, with Bjorkman (2017) include something like animacy as well as their particular gender specification. Each of these three features contrasts with the other two and with the absence of any gender/ class feature. We also assume, with Bjorkman (2017), that singular [sg] is the marked number feature.
However, we follow Kramer (2009; in placing the gender features on the nominal categorizing head n. We assume that the φ head above Number, where Bjorkman places [masc] and [fem], is actually the locus of person features like [participant] and [author]. 16 Third-person pronouns either have no marked features on φ, as we assume for English, or depending on the language, may lack person specification altogether (Déchaine & Wiltschko 2002;Béjar 2003).
We also assume that at this stage, English nouns like sister, policeman, and turnip, as well as names like Susan, Richard, and Thailand, carry the contrastive features [fem], [masc], and [inanim], respectively. Further, we assume that when nouns like teacher, doctor, and person, and names like Kelly and Pat, are used to refer to individuals of known binary gender at this stage, the contrastive feature matching the individual's binary gender is obligatorily inserted on the nominal head n. 17 The third-person pronominal vocabulary items are given in (11). These are essentially the same as those proposed by Bjorkman (2017: 7), the only difference being the syntactic position of [fem] and [masc]. 13 The theoretical status of feature geometries has been challenged by Harbour & Elsholtz (2012), Harbour (2016), and Cowper & Hall (2019). Nothing in this paper hinges on whether dependencies among interpretable formal features derive from a feature geometry or from a contrastive hierarchy, as Cowper & Hall (2019) propose. 14 See Hall (2007) and Dresher (2009)  We propose the structure in (14)  We propose that for quantified antecedents like those in (12) and (13), there is a close relationship between the quantifier, which occupies a D Q head above Number, and the Number head itself. We provisionally stipulate that the features of the number head are copied to D Q , and thus become features of the quantified nominal as a whole, while features of the n head lower in the structure are only optionally copied to D Q . 21 The referential properties of a definite, non-quantified DP presumably require that the gender features of n, when present, are obligatorily copied to the D level. 22 Under this view, if a 18 In fact, Conrod (2019: 110) finds that in these quantifier-bound contexts, speakers prefer they to either he or she. 19 As pointed out by a reviewer, there are two possible reasons for a hearer to find (13) ill-formed with their.
One possibility is that it might be seen as a number mismatch: every book is grammatically singular, and their can be interpreted as spelling out a plural feature structure. The other, which is the one relevant here, is an animacy mismatch: every book is singular and inanimate. Inanimate is a contrastive feature in the system, and the Vocabulary Item it spells out both singular and inanimate, blocking the insertion of they unless inanimate is absent from the pronoun. 20 Following van Gelderen (2013), we assume that third-person pronouns are DPs, while participant (first-and second-person) pronouns are φPs. In line with the assumptions of Bare Phrase Structure (Chomsky 1995), we do not notationally distinguish heads from maximal projections when they do not branch. The node n should thus be read as a non-branching nominal complement of Num, possibly bearing one or the other of the contrastive gender features masc and fem. In a full, lexical nominal, n will take an acategorial root as a complement (Borer 2005). 21 This proposal resonates to some extent with Conrod's (2019: 216) proposal that in bound-variable pronouns, the pronoun does not raise from n to D. 22 We are not concerned here with the details of the syntactic mechanisms that accomplish the copying. Kučerová (2018) discusses mechanisms of "natural" gender marking and gender agreement with (lexically masculine) profession nouns in Italian, though the existence of non-binary genders is not acknowledged in that paper.
quantified antecedent bears the feature [inanim], that feature will always be accessible to the binding relation between the antecedent and the quantifier-bound pronoun, and will have to be spelled out, while the lower gender features on n may or may not be accessible. At Stage 1, then, all three features [masc], [fem], and [inanim] are contrastive in the pronoun system. Many nouns, like actor, actress, mother, and brother, and proper names like Susan and David, also carry contrastive gender features, and other nouns, when used to refer to individuals of known gender, bear an obligatorily inserted contrastive gender feature. Except for pronouns bound by quantified antecedents, as described above, coreference requires that the features of the pronoun match those of its antecedent. Singular they in other contexts, whether A-bound by a non-quantified antecedent or not bound at all, is thus possible only when the gender of the antecedent is epicene or unknown, and the antecedent thus bears none of the three gender features; in all other cases, either he or she is required.

English pronouns at Stage 2
Let us turn now to Bjorkman's Innovative variety, which we refer to as Stage 2. We claim that in fact, there is no change whatsoever in the status or position of gender features in the pronoun system between Stage 1 and Stage 2: all three gender features remain contrastive, and for nominal antecedents bearing gender features, Stage 1 and Stage 2 are identical. The difference between Stage 1 and Stage 2, we claim, lies in the way nouns are specified in each speaker's lexicon, and in whether gender-nonspecific nouns referring to human beings are obligatorily assigned a binary gender feature. Recall that at Stage 1, nouns referring to people are, in any given sentence where the gender of the referent is known or assumed, systematically assigned either [masc] or [fem] corresponding to that referent. At Stage 2, however, the rule inserting a contrastive gender feature is optional: nouns like teacher and friend need not be assigned gender features even if the gender of the referent is known or assumed. Nonetheless, there remains at Stage 2 for any individual, a subset of nouns, like mother, father, sister, brother, actress, and policeman, as well as certain proper names, that lexically bear contrastive gender features; i.e. the gender feature is present on the noun in the speaker's lexicon, not assigned based on a given referent. 23 Since gender features are contrastive, a singular pronoun whose antecedent carries either [masc] or [fem] -either lexically or based on the known or assumed gender of the referent -must be spelled out with he or she. Individual speakers will differ, based on their own experience, as to which nouns, and which proper names, lexically bear contrastive gender features, and in how readily unfamiliar proper names are assigned a lexical gender specification. In addition, the possibility exists that a Stage 2 speaker may encounter an individual of non-binary gender whose pronoun of reference is they but whose name (e.g., Mary), carries a contrastive gender feature in that Stage 2 speaker's lexicon.

(15)
Mary i explained that they i had to leave early.
A Stage 2 speaker has several options in this situation. First, they could adjust their lexicon by deleting the contrastive gender feature from that particular proper name. Mary would then join the class of given names like Kelly, Alex, and Morgan, which are not marked for gender, and (15) would be grammatical. This predicts, somewhat implausibly, that once a Stage 2 speaker has accommodated their lexicon as just described, any instance of Mary, regardless of the gender of the referent, should be able to serve as the antecedent to they.
A second, more plausible, option would be to add a new lexical entry for Mary to their lexicon, homophonous to the existing entry, but with no marked gender feature. This new lexical item would be specified as denoting an individual whose pronoun of reference is known to be they, or might even be restricted to refer only to the particular non-binary individual in question. A sentence like (15) would thus remain ungrammatical, unless it referred specifically to the individual in question, or to some other individual with the relevant property. Essentially, this amounts to marking well-formed uses of (15) as exceptions.
A third option -which we would characterize as unhelpful (and even bigoted) but nonetheless a logical possibility -would be for the Stage 2 speaker to simply refuse to use the individual's correct pronoun, on the grounds that to do so would be grammatically ill-formed. As can be confirmed by a cursory online search, this option is frequently chosen (even on occasion by some linguists), quite explicitly and publicly, by people with an agenda that has very little to do with grammar, and pertains more to the attempted exclusion of transgender and non-binary individuals. 24 The final option would be to change the status of gender features altogether, making them optional modifiers 25 <masc> and <fem> rather than contrastive features whose absence carries meaning, moving the speaker fully to Stage 3. At this stage, which is to our knowledge the last stop on this trajectory, they can be used to refer to any non-inanimate singular individual, whether or not the antecedent is linguistically present, and whether or not the antecedent is a nominal bearing semantic gender features. He and she are also available, spelling out <masc> and <fem> respectively, and may indeed be required in certain situations (as when the speaker knows that the referent's pronouns are he, or she), but their use is always grammatically optional, since the gender features they bear are grammatically non-contrastive. This stage aligns most closely with our own judgements, and with the judgements of our consultants.
An important point to be made here is that this fourth option is also available to a Stage 1 speaker faced with data like (16), repeated from (6).

(16)
Stage 2 singular they (antecedent of known gender, but ungendered description/name): a. Kelly i said they i were leaving early. b. My eldest child i got a bicycle for their i birthday.
We suspect that many Stage 3 speakers, and in particular those who have greater familiarity with non-binary individuals (e.g., those who have non-binary acquaintances, friends, or family members; see Ackerman et al. 2018) may actually never have passed through Stage 2 at all, having instead simply changed the status of the features [masc] and [fem] to optional adjuncts <masc> and <fem> in the first instance. This move is essentially the grammatical manifestation of an understanding that so-called "natural gender" is not a binary property. For those speakers who have instead made case-by-case changes to the gender specifications of nouns in their lexicon and are thus at Stage 2, it would seem that shifting into Stage 3 involves making a separate conceptual leap away from the cultural assumption that all persons can be categorized according to a gender binary, a leap that requires engaging with wider socio-cultural changes regarding gender and gender identity. But no matter which path is taken, at Stage 3, the morphosyntactic and sociocultural changes dovetail.
However, for a Stage 2 speaker, faced with a single situation that their grammar does not accommodate, the second option described above -creating homophonous entries for a single form like Mary, one with a gender feature and the other without -has the smallest effect on the grammar as a whole, and this is plausibly the option that a Stage 2 speaker would choose in such a situation. We speculate that this is where many speakers of English are currently situated: effectively marking exceptional cases to accommodate non-binary individuals of their acquaintance, but without making overall structural changes to the status of gender in their grammars. In the long run, however, given the increased visibility of individuals of non-binary gender, this approach leads in principle to a less efficient lexicon, rife with homophonous pairs of lexical entries, one member of each pair carrying specific idiosyncratic pragmatic constraints. At the same time, these same exceptional cases, having expanded the distribution of singular they, reduce the empirical pressure for a systemic change in the status of gender features in the pronoun system.

Comparison with Bjorkman's (2017) account
In this section we briefly summarize Bjorkman's proposed analysis of Stage 1 and Stage 2 they, assessing the merits and shortcomings of the account, both empirical and theoretical, and considering how it fares in comparison to the account presented in Section 4.

The Conservative variety
Using a realizational model of morphology, Bjorkman argues that in the Conservative variety (our Stage 1), there is a contrastive three-way gender distinction, with marked masculine (masc) and feminine (fem) contrasting both with each other and with an unmarked neuter. Other features in the system are singular (sg) and inanimate. Third-person pronouns are realized as in (17) 19c). However, since a bound variable can also be a bare NumP, it can lack gender specification entirely, even if its antecedent is singular and of known gender, as in (19e) and (19f). 26 The pronouns in (19c) and (19d) are thus in principle ambiguous between a φP with no gender specification on φ and a bare NumP, while the pronouns in (19e) and (19f), whose antecedent is lexically marked with [masc], can only be a bare NumP.
(19) a. Any girl i who needs help should speak to her i teacher. b. Every boy i who does his i best will pass the course. c. No teacher i who mistreats their i students will be promoted. d. If any wine i is left after the party, it i will be thrown out. e. There's not a man i I meet but doth salute me / As if I were their i wellacquainted friend (Shakespeare, 1623, A Comedy of Errors) f. Ye knowen wel that euery lusty knight i / that loueth paramours and hath his i might / were it in Engelond or elliswhere / They i wolde hir i thankes wilnen to be there (Chaucer, Knight's Tale 2113-16, cited in Balhorn 2004: 92) At Stage 1, then, English has a fully contrastive, ternary gender system, both for us and for Bjorkman. A singular pronoun whose antecedent is marked as masc or fem must be realized as he/him/his or she/her, respectively. 27 Epicene they arises with singular animate referents of unknown or non-unique gender, realizing a φP bearing neither masc nor fem. The only exception is with quantifier-bound pronouns, which can, for Bjorkman, consist of a bare NumP with no gender specification. While Bjorkman's account, by our estimation, correctly describes the distribution of pronouns at Stage 1, the stipulation that quantifier-bound pronouns optionally spell out either φP or NumP is theoretically worrisome. 28 Ideally, it should be possible to identify some other properties (we know of none) that fall out from the syntactic category of the pronoun in these instances; if there are indeed no such properties, then the account is ad hoc. Empirically, this stipulation corresponds to our proposal that in quantified DPs, the features of the Number head are obligatorily copied to D Q , while the features of n are copied only optionally. Both approaches require further theoretical and empirical support, a question we leave for future work.

The Innovative variety
In Bjorkman's Innovative variety (our Stage 2), the contexts in which singular they appears include a wider range of animate antecedents of known gender, as in (20) repeated from (3) above. 26 An anonymous reviewer suggests that not a man in (19e) might be an epicene use of man, but euery lusty knight in (19f) is almost certainly not epicene. 27 As pointed out by a reviewer, the situation can be somewhat more complicated; for example, at a costume party where a guest whose pronoun of reference is he happens to be dressed as a nun. In such a case, either (i) or (ii) is well-formed, depending on whether the speaker is referring to the individual wearing the costume (i), or to the character being performed (ii). This situation is similar in some respects to what happens when describing works of art depicting people, as in (iii) and (iv).
(i) The nun has lost his rosary.
(ii) The nun has lost her rosary. (iii) Mona Lisa has lost its frame.
(iv) Mona Lisa has lost her frame. 28 As pointed out by a reviewer, the account of bound variable pronouns in Déchaine & Wiltschko (2002 has a consistent association between the semantic type of a pronoun and its syntactic projection, and thus does not suffer from this problem. However, Déchaine & Wiltschko place person, number, and gender features on the same projection (φP), and analyze third-person pronouns as φPs. Since it is not at all clear how such an account would permit singular they at Stage 1 in quantifier-bound contexts such as those in (12c) and (19e,f), we restrict our attention to the modified account proposed by Bjorkman (2017).
(20) a. %The professor i said they i cancelled the exam. b. %Our eldest child i broke their i leg. c. %I'll let my cousin i introduce themselves i .
Crucially, in each of these sentences, the gender of the antecedent is known to the speaker, and may be binary. In the Conservative variety, the epicene interpretation of singular they would not be available here, and the pronoun would obligatorily realize contrastive masc or fem, as applicable. 29 At the same time, the gender features seem not to have not lost their contrastive force entirely, since Bjorkman points out that sentences like (21) remain ill-formed for Stage 2 speakers.
(21) a. *My father i said they i were leaving tomorrow. b. *Janet i left their i book here.
Faced with this apparently inconsistent behaviour of the features [masc] and [fem], Bjorkman proposes that for speakers who accept the sentences in (20), but reject those in (21), the two gender features in the pronoun system are no longer contrastive, but are optional, interpretable, adjunct features in Wiltschko's (2008) sense. The absence of both <masc> and <fem> on φ thus does not imply that the referent of φP is neither masculine nor feminine, and thus does not restrict such a φP to epicene contexts. This account straightforwardly predicts that sentences like those in (20) are well-formed, but does not explain why those in (21) are unacceptable. If the gender features are truly optional adjuncts, they should pattern as other optional semantic content does: omitting them should never cause ill-formedness. 30 On the assumption that the nouns man and mother carry the features <masc> and <fem> respectively, while the nouns person and parent carry no gender features, the choice to use they instead of he or she in (21) might be expected to have the same status as using person or parent instead of man or mother in (22). (22) a. My father is that well-dressed person over there. (cf. that well-dressed man) b. Janet is the parent in the back of the classroom. (cf. the mother) Given Bjorkman's analysis, then, the account of the ill-formedness of the sentences in (21) will not be found in the narrow syntax. Bjorkman proposes that it follows instead from a dynamic condition on feature matching in discourse, which requires that "referential pronouns can only be interpreted as referring to a previously-introduced referent if they bear a superset of the features that have already been associated with that referent in a discourse. In other words, a pronoun can add to the linguistic features associated with a referent, but it cannot underspecify them." (Bjorkman 2017: 11). The effect of this proposal is essentially to smuggle contrastive gender features back into the system. By definition, adjunct features cannot be syntactically obligatory. If Stage 2 speakers do not have grammatical, contrastive gender features in their pronoun systems, then the choice of gender-marked pronouns like he and she cannot be enforced by the grammar. 29 It may be that a Stage 1 speaker might resort to sentences like (20) when they specifically wish not to reveal the gender of the referent, thus producing an utterance that is, strictly speaking, ill-formed at Stage 1. 30 Bjorkman cites Kramer (2015) in support of the idea that non-contrastive features can sometimes be obligatory. As far as we can tell, the distinction Kramer makes is not between contrastive and non-contrastive gender features, but rather between semantically interpretable (so-called natural) and semantically uninterpretable (so-called arbitrary) gender features, both of which are present in Amharic, and both of which seem to behave contrastively. We therefore keep to our assumption that non-contrastive adjunct features are never obligatory.
It must be noted that this requirement holds only of the featural structure being spelled out, and not of the vocabulary items themselves, since Stage 2 speakers have no trouble using the underspecified vocabulary item they to refer to a plural, gendered antecedent like women, as in (23).

(23)
The women i said that they i were leaving.
In (23), the effect of Bjorkman's proposed dynamic requirement here is that the φP spelled out by they must bear the feature <fem>. But since there is no vocabulary item in the system that spells out <fem> without also spelling out the contrastive feature [sg], they is inserted.
There is a problem with the requirement, however. As Bjorkman (2017: 11) describes it, its effect is that "a pronoun can add to the linguistic features associated with a referent, but it cannot underspecify them." In other words, the featural representation that a pronoun spells out cannot be less specific than that of its antecedent, but it can be more specific. Consider the sentence in (24).
(24) *The women i said that she i was leaving.
Assume, with Bjorkman, that singular is marked relative to plural in the pronoun system, and that women bears a gender feature <fem>. Featurally speaking, the women is specified as <fem>, but bears no number feature. Suppose that the node spelled out by the pronoun bears both <fem> and [singular]. The pronoun will therefore be spelled out as she. In accordance with Bjorkman's requirement, the pronoun bears a superset of the features of its antecedent, wrongly predicting that (24) should be acceptable.
Another question about the proposed dynamic condition on feature matching is its status in the theory. Is it a (presumably universal) property of how coreference is resolved in discourse, or is it instead a (necessarily learnable) property that one language may have and another may lack? Bjorkman does not discuss the question, but on the assumption that the condition lies outside the grammar proper, we will assume that it is intended to be universal. 31 One could imagine a revised version of Bjorkman's dynamic requirement, such that its effect is limited to only adjunct features. Under such a view, it would be instructive to look at number marking on nominals and pronouns in a language like Halkomelem, where number has been shown to be an optional adjunct feature (Wiltschko 2008), but where both singular and plural pronouns are available (Wiltschko 2002). If Bjorkman is correct, the presence of plural marking on a noun should force any pronoun coreferential with it to take plural form, while a plural-referring but unmarked noun should be able to serve as the antecedent of a plural-referring but unmarked pronoun. Without a condition such as this one, one might expect there to be no particular connection between the presence of plural marking on a pronoun and its presence or absence on a coreferential pronoun.
However, one need not go so far afield as Halkomelem number marking to test whether a universal condition of this sort can be maintained. It should, in fact, be applicable in the English of Stage 3 speakers, as long as (a) these speakers still have the pronouns he and she in their system, spelling out optional adjunct gender features, and (b) these speakers also have, in their lexicon, some nouns (like stewardess, policewoman, actress, chairman, etc.) that can only felicitously refer to individuals of known binary gender, with some notable exceptions (see Ackerman 2019 for felicitous examples based on situational context, as in At the Halloween party, I saw that the stewardess i left their i hat in the kitchen, but I don't know who i it was). As we will see in the next section, this prediction is not borne out.
Furthermore, though Bjorkman describes the judgements we have reported as our Stage 2 as the Innovative pronoun system, we claim that this is not in fact the most innovative variety in current use.

The even more innovative variety: Stage 3
It is at Stage 3 that the differences between our account and Bjorkman's come fully into focus. Recall that at Stage 3, they is completely unrestricted in referring to third-person, singular, animate antecedents. In particular, it can be used in sentences like (25), where the antecedent is a proper name with strong gender association (25a) or a semantically gendered noun (25b). 32 (25) a. Sir Paul i has always played their i guitar left-handed. b. My grandmother i always liked it when we asked them i about their i childhood.
For us, the difference between Stage 2 and Stage 3 is clear: while at Stage 2 the masculine and feminine gender features were still fully contrastive, at Stage 3 they have lost their contrastive status and have become completely optional modifier features. This straightforward account of the difference between Stage 2 and Stage 3 is not available to Bjorkman's analysis, since there, even at Stage 2 the features are claimed to be optional and non-contrastive. Nor, we assume, can it plausibly be that Stage 3 speakers have lost the dynamic condition on feature marking in discourse, since that condition is not parametric. Nor can it be that gender features are entirely absent from the Stage 3 pronoun system, since even at Stage 3 he and she are optionally available. The difference can therefore only be that words like grandmother and Sir, and proper names like Paul, have lost their gender feature specification altogether. However, even for Stage 3 speakers, nouns like grandmother and chairman are still strongly gendered, though they can serve as antecedents to singular they when the occasion calls for it (such as in the case of an individual who uses either of the labels grandmother or chairman, and uses the pronoun of reference they). We conclude from this that Bjorkman's account of what we call Stage 1 and Stage 2 cannot easily be extended to account for the Stage 3 system, and that the account proposed here is to be preferred.

Implications
Under the account proposed in Section 4, the only change required between Stage 1 and Stage 3 is in the status of the masculine and feminine gender features: the syntactic structure of the pronouns is otherwise completely unchanged. Since they can always refer to an animate, singular individual, the presence or absence of gender in the denotation of a specific noun is less important, and has no consequences for the well-formedness of pronoun-antecedent pairs. In fact, all three of the sentences in (26) are in principle grammatically well-formed at Stage 3, though the circumstances under which it is appropriate to use them are different. 33 (26) a. My mother i left her i coat here. (My mother refers to an individual whose pronoun of reference is she/her.) b. Your mother i left their i coat here.
(Your mother refers to an individual of any gender, binary or not, which may or may not be known to the speaker and/or the hearer.) 32 Note that Stage 3 speakers also accept his in (25a) and her in (25b). 33 We intend in all three of these sentences that the noun mother should be interpreted as the birthing parent of the speaker or addressee (as applicable). As one reviewer points out, the term mother can be interpreted in other ways, which increases the number of possible interpretations. For example, a second definition of mother could be a person of any gender in the social role of 'mother', in the sense of a caretaker. This definition could easily accommodate examples like (26c).
c. Your mother i left his i coat here. 34 (Your mother refers to an individual (possibly transgender) whose pronoun of reference is he/him/his, and who is the mother of the addressee of the sentence.) Under the account we have proposed here, the change in the English pronominal system at Stage 3 to accommodate this new use of singular they is subtle. In fact, the structure of the pronominal features remains exactly as it was; all that changes is the status of the gender features themselves, specifically, whether they are required contrastive features or optional modifier features. It is possible that this relative subtlety may explain why some speakers find the change in usage difficult to acquire with fluency, despite their best intentions. The nuance of our analysis for Stage 2, with contrastive [masc] and [fem] in the pronoun system as at Stage 1, but a smaller inventory of lexically gendered nouns and an optional rule assigning "natural" binary gender to ungendered nouns, accounts for those speakers who consider themselves to be in solidarity with gender-diverse communities, but may still struggle to abandon the more conservative system. While some speakers find the use of singular they in the innovative Stage 3 contexts described here to be objectionable for social reasons, these objections are all too frequently packaged as an effort to defend the grammar itself, or, in the case of linguists who take this position, as deriving inexorably from the grammar. Singular they -and non-binary singular they more specifically -provides an apt example of how grammar and social meaning are not so neatly separated. With respect to pronouns, there is no apolitical stance (Zimman 2016): as one of the primary linguistic tools that speakers use to refer to other individuals and implicate them in social categories and relationships, pronouns may very well be especially susceptible to modification in response to social movements (Bodine 1975).
As linguists (of all subdisciplines), we are often tempted to apply a putatively objective lens to our study of language. But it is crucial that we not operate in a vacuum, or assume that even our theoretical analyses have no concrete effect on the people whose language we are studying and making use of. We would like to suggest that linguistic work of all sorts cannot be entirely divorced from the social context in which language is used and from the speakers themselves. In studying innovative manifestations of gender in pronouns, this segregation of inquiry has historically led linguistic researchers to ask very different questions from those that matter to the communities impacted by that research, focusing more on the probable "success" of a given pronoun and hypothesizing about its odds for universal adoption (e.g., Baron 1986;Balhorn 2004;inter alia). We should also bear in mind the ways our work can be weaponized by those wishing to further marginalize already marginalized groups, regardless of the work's theoretical elegance, or its importance for purely theoretical questions.
In particular, we would do well to direct our attention to how pronouns are actually used, especially by those most affected by how gender is marked, leveraging our theoretical insights to advocate for trans-affirming language practice. As we believe we have demonstrated in this paper, doing so poses no risk to the scholarly advances to be made.