Buyeo languages
The Buyeo languages represent a hypothetical family of languages that combines the languages of the ancient empires of Goguryeo , Buyeo and Baekje of the Korean peninsula into a single unit. This grouping is mainly based on Chinese sources that describe these languages as very similar - since this similarity can only be proven fragmentarily, however, it is difficult to prove the existence of this language family.
The hypothesis is so interesting because all these languages have certain similarities with Old Japanese , which is why some researchers speak of a Japanese-Goguryeo language family. This would indirectly call into question the existence of the also hypothetical Altaic language family , as the Buyeo languages are explicitly differentiated from the language of the Silla empire and thus from Old Korean .