Translation of "Linguistics" in Chinese

- My field of study is linguistics.
- My major is linguistics.

我的主修是語言學。

My major is linguistics.

我讀語言學。

The book's not about linguistics.

這本書不是語言學。

He is absorbed in the study of linguistics.

他沉迷于语言学的研究。

He is at home in phonetics as well as linguistics.

他不只精通語言學，也精通語音學。