Lexical growth and grammatical competence: potential risks for children with a hearing deficiency

Language acquisition is a step-wise process. Some features of the mother language are acquired earlier than others. The first utterances of the child consist of names and single words. In a next step, the child simplifies the input to (mainly) binary combinations of words with denotational content {e.g. bear sweet} and operator-like words with immediate situational deixis {e.g. that bear}. The combinatorial use of words enhances the opportunities to acquire new words. The number of words productively used within the binary constructions rises to something between 300 and 500 (first lexical spurt) (Bates, Dale and Thal 1995). 1.1 The acquisition of I-marking and D-marking in Dutch Around the second birthday the binary utterances get systematically enriched by grammatical markings. The first set of markings are auxiliaries, modal verbs, copulas and finite verb endings. I will label them I(nfl)-marking. In the stage of binary constructions, Dutch children use at first modal verbs as a kind of pre-grammatical operator, see (1)a (Jordens 2002, Van Kampen 2005). These modal verbs have an affective and social value. They are speaker/hearer oriented in the situation at hand. It is only in the next stage that the use of modal verbs is extended as in (1)b. Moreover, I-marked predicates with finite lexical verbs now appear systematically. (1) a. wil beer / magwel koekje eten (wanna bear, (I) may indeed cookie eat) b. beer {is/wil/moet/gaat}slapen (bear is/want/must/goes sleep) c. beer slaapt (bear sleeps) The acquisition of I-marking can be captured in a longitudinal graph. The Io-graph in (2) marks Sarah’s rising percentage of finite verbs towards the adult norm in some 20 weeks