据我们所知，其中最古老的语言是印欧语系。 远在石器时代人们就开始使用印欧语了。

The oldest of these, as far as we know, was the Indo-European family of languages, which were beginning to be spoken clear back during the Stone Age.

youdao

据我们所知，其中最古老的语言是印欧语系。 远在石器时代人们就开始使用印欧语了。

The oldest of these, as far as we know, was the Indo-European family of languages, which were beginning to be spoken clear back during the Stone Age.

youdao