Summary The study of language acquisition across languages shows that there are different orders and rates of acquisition depending on each language's individual grammatical features and characteristics. This study investigates the acquisition of Arabic gender and number agreement of adjectives and verbs with corresponding nouns in the performance of ninety-eight Saudi children between the ages of six and twelve years, and also of seven adults, in a cross-sectional study. Their comprehension and production is investigated through using a picture selection test and an elicited production test. Three other children between the ages of 1; 4' and 4; 5 have been tape recorded to investigate their language productivity and language input in a longitudinal study.
Summary The study of language acquisition across languages shows that there are different orders and rates of acquisition depending on each language's individual grammatical features and characteristics. This study investigates the acquisition of Arabic gender and number agreement of adjectives and verbs with corresponding nouns in the performance of ninety-eight Saudi children between the ages of six and twelve years, and also of seven adults, in a cross-sectional study. Their comprehension and production is investigated through using a picture selection test and an elicited production test. Three other children between the ages of 1; 4' and 4; 5 have been tape recorded to investigate their language productivity and language input in a longitudinal study. Our main results indicate that grammatical forms become productive at a very 2 young age- 16.22 , while mastering of the forms occurs at a later age between eight and twelve years, with some forms being mastered even after the age of twelve. Our findings, on the whole, show that the gender system is mastered between the ages of eight and ten, while errors in the use of the plural system are retained even after the age of twelve. The number system findings also show that singular forms are mastered earlier than dual forms, while dual forms are mastered earlier than plural forms.
In addition, the study reveals that transparency, form frequency, and language input and CDS are some of the main factors contributing to the early mastery of grammatical forms, while abstractness and irregularity in grammatical forms, opaque agreement, and infrequency of language input and CDS result in later acquisition and mastery of grammatical forms. In general, our results show that the rate of mastery of the Arabic gender system is consistent with the rate of acquisition of the Welsh gender system. Acquisition of the Arabic number system appears consistent with the late acquisition of the German number system, while the late mastery of the Arabic verb system is consistent with Modem Greek acquisition. Finally, it has become clear that there is a need for further studies on the acquisition of different Arabic dialects and on the main factors behind the late acquisition of Arabic. However, this study has answered many important questions. It has also highlighted areas to investigate, and hopefully these areas will be addressed in future research.