In the process of foreign language understanding, learning and using, thinking in the mother tongue will inevitably lead to the intervention of strong mother tongue contextual knowledge in the brain, and then activate the mother tongue expressions that match the mother tongue contextual knowledge. The object of second language acquisition is influenced by age, the current study set out to examine to what degree of acquisition (AOA), defined as a learner's first intensive exposure to a second language (L2) environment, mediates the final state of poster, spoken vocal accommodation. The more the students use mother tongue thinking in English writing, the shorter the writing text. This negative correlation is most prominent in the text-generation activities of writing. In fact, similar experimental findings were found in early studies. For intermediate learners, the longer the code-switching takes place in second-language writing, the shorter the text will be. Therefore, the research topic of this paper is the influence of mother tongue thinking transfer on second-language writing.