Stylistic differences between children and adults in cognitive learning can account for differential SLA results. Previous research mainly dealt with interlingual influences, focusing on L2 acquisition of the phonetic system. The present study made an investigation into Chinese learners’ acquisition of the English articles and revealed that influences of adult cognitive learning style on input processing also exists in the learning of grammar. Such influences occur not only between the native and the target language, but also in the development of intralingual knowledge. Empirical data of the present study show that adult L2 learners tend to adopt assimilation to process input and this cognitive learning style may impede the interlanguage development.