THE AGE FACTOR IN LANGUAGE DEVELOPMENT THEORIES AND ITS IMPLICATIONS FOR ACQUISITION AND TEACHING

This research investigates the progression of grammatical complexity in English language textbooks designed for various age groups, ranging from young children to adults. By analyzing four textbooks—Smiles (ages 6-7), Wider World 1 (ages 11-12), Solutions (ages 14-15), and English File (ages 18+)—the study explores how linguistic theories, particularly the Innate Hypothesis and the Critical Period Hypothesis, are implemented in practical language teaching. A comparative method was used to evaluate the curricula of these textbooks, focusing on morphology, syntax, and phonology. The findings reveal a clear increase in grammatical complexity, corresponding to the learners’ cognitive and linguistic development stages. For instance, Smiles introduces basic grammatical structures and phonetics suitable for young children, while English File covers advanced grammar and detailed phonological content for adult learners. This study highlights the importance of aligning language instruction with learners’ developmental stages and provides insights for educators to adapt their teaching strategies accordingly. The results support the claim that early exposure to language, as well as the adaptation of teaching methods to different age groups, enhances language acquisition.