I used to be a linguist till I become a writer.

过去我是语学家, 后来成了作家。

He used to be a linguist till he turns writer.

他过去是语学家, 后来成了作家。

"This well-known linguistic learned tribal languages in the field, not from books in the library."

"这位著名的语学家是在实地学会部落语,而不是在图书馆的书籍上学会的。"

Historical linguists have to identify and classify families of related languages in a genealogical family tree, and to reconstruct the protolanguage.

历史语学家们通过对语中相关语进行甄别，勾画出家族谱图，从而重新构建语的原始语。