This paper claims that the hierarchical structure of morphosyntax is mapped onto a linear sequence of elements with prominence and different strengths of juncture, which play a role in parsing the structure intended by the speaker. The mapping of left-branching and right-branching structure shows asymmetry in the strengths of juncture. This junctural asymmetry comes from the phonetic implementation of speech signals. It is argued that the strong juncture in left-branching structure makes it quasi-compound. Unmarked word-stress location works as a constraint on complement movement, deriving left-branching from right-branching structure in the base, thus taking the place of a head-directionality parameter. This analysis therefore dispenses with the need for linear information in morphosyntax.