The Acquisition of Verbal Morphology in Persian

This study constitutes the first focused description and analysis of the acquisition of Persian inflectional morphology. It focuses on the order in which children acquire the verbal morphological system and also considers factors that influence the order of acquisition. Three monolingual Persian children with the age range of 1;8 to 3;1 were videotaped at one-to-four month intervals in naturalistic interaction with their mothers. Based on transcription of these sessions, the point of acquisition of verbal inflections was determined following two sets of criteria: productivity and contrastive use of inflections (Pizzuto and Caselli, 1994, adjusted to Persian) and deployment of morphemes in obligatory context (Cazden, 1968). The main finding is that although some shared order of emergence and development of productivity can be identified, it is not possible to talk about distinct stages in the acquisition of verbal morphemes, such that the acquisition of number, aspect, mood, tense or person could be said to occur in any set order. For example, in two of the children Person and Mood contrasts develop before AFF/NEG and Tense contrasts, followed by Number and Aspect contrasts; however, Person and AFF/NEG inflections are acquired to full criteria at the same MLU in each child (i.e., 1.5 and 1.9, respectively). The different patterns of productivity along with different pictures of development observed for each of the three children raise the question of what determines which forms will be learned and in which order. The frequency of occurrence of verbal morphemes in the input speech of the three mothers was found to be related to the order of emergence, productivity and contrastive knowledge of the morphemes in the children, whereas the role of typological factors (i.e., perceptual salience and transparency) was not straightforward. The results of the study are consistent with a constructivist account of language acquisition, which sees the acquisition of morphemes as a gradual process activated following considerable exposure to the input in different variations in terms of types and tokens. Furthermore, the findings confirm the interdependence of lexical and morphosyntactic development by demonstrating that it is prompted by an increase in the size of the lexicon over a certain level