Abstract:
This qualitative study is conducted to answer four questions: First, whether there is a difference between the grammatical competence development of a group of children aged 2.6 (two years and six months) and a group of children aged 3.6 (three years and six months). Second, whether there is a significant difference between the two age groups concerning their Mean Length of Utterance (MLU). Third, whether there is a relationship between the children’s MLU and that of the caretakers. Fourth, whether the normal limit proposed by Brown (1973) is observed in the acquisition of Persian. To this end, language samples of six children and their caretakers’ were recorded during a six-week period and studied afterwards. The results indicated neither an unequivocal yes nor a definitive no answer to the question of age difference and grammatical competence development, that is to say, in some cases there was a difference whereas in some other cases there was no difference at all. As for the difference between the two age groups concerning their MLU, there was a significant difference between the two. However, no significant relationship was found between the children’s MLU and their caretakers’. Finally, the limit proposed by Brown (1973) was observed in the acquisition of Persian.
Machine summary:
"Keywords : first language, child directed speech, mean length of utterance, grammatical competence development, grammatical judgment test Introduction In spite of the fact that great strides have been taken to explain first language acquisition, due to the paucity of research evidence on the one hand, and the inherently complex nature of the phenomenon on the other, it is still difficult to explain such a feat as adequately as possible.
(Lieven, 1978) In this regard, Peccei (2006) points out that Child Directed Speech and the early social interactions between mothers and babies has been a response to Chomsky's (1987) 'poverty of stimulus' argument according to which it is actually impossible for children to acquire a system as abstract and complex as human language without some prior inborn knowledge about the way it works.
' Nevertheless, Brown (1973, cited in Johnson, 2001) had earlier pointed out that MLU would be less informative once children had reached stage five of L1 acquisition because differences in utterance length would then reflect properties of particular interactions rather than new language knowledge.
5 Session Figure 6 shows Parmis’ and her caretaker’s MLU Regarding the first research question as to whether there was a difference between the two age groups concerning grammatical competence development, the answer is neither an unequivocal yes nor a definitive no.
With respect to the second research question, a nonparametric Mann- Whitney U test was run which was due to the limited number of participants in the study (N=6) and the following result was obtained indicating that the difference between the two age groups concerning their MLU is significant."