The optional subject phenomenon in young children's English: a case study.

Recent treatments of the optionality of sentence subjects in young-children's English have sought to link this phenomenon, and its eventual demise, to the development of the child's verb inflection system or to a parameter-resetting within the INFL ('inflection') constituent of the child's grammar. It is claimed that subject optionality disappears when these developments occur. The case-study reported here investigated the productive language of an English child between 2;5 and 3;0. It found that subjects were no longer optional at a stage when none of the reflexes of INFL claimed in the literature to be associated with the disappearance of subject optionality had yet been acquired. The possibility that subjects were present only when communicatively required was rejected. The frequency of subject realization of a Japanese child aged 3;0 was used to provide a measure of expected realization when subjects are not grammatically required. It is concluded that subject obligatoriness in English may be acquired as a characteristic of the language sui generis, independently of developments elsewhere in the child's emerging grammar.