Several observational studies suggest that the infant vocalization towards language acquisition develops through interactions with caregivers. However, what kind of underlying mechanisms works and how caregiver's behavior affects on this process have not been made clear since it is very difficult to control the infant vocalization. In order to attack this issue, we built an infant-like vocal robot "Lingua" as a controllable vocal platform. Lingua has two features; infant-like voice and high articulation capability. The shape of its vocal tract resembles that of a 6-monthold infant based on the anatomical data, and this may contribute to the former. 7-DOFs for articulation in the tongue is realized by sophisticated design of linkage mechanisms inside miniaturized vocal tract for high capability of its articulation. Preliminary experiments showed that the robot succeeded in vocalizing almost the same fundamental frequency vowel-like utterances similar to that of an infant.