He recognized that Sanskrit, the language of India, was related very closely to Latin, Greek, and the Germanic and Celtic languages.
他认识到梵语，即印度的语言，与拉丁语、希腊语、日尔曼语和凯尔特语密切同源。
《柯林斯英汉双解大词典》
2
In the 18th century, scholars who have studied the ancient languages, Sanskrit, Latin and Greek, noticed that these three languages had many similarities.
18世纪研究古代语言（梵语、拉丁语和希腊语）的学者们注意到这三种语言有许多相似之处。
3
Proto-Indo-European is a reconstructed language, meaning, it is what linguists concluded a parent language of Sanskrit, Latin and Greek would have to be like.