Original sentence: Most linguists believe these should be grouped together as a sub-group to Japonic languages, known as Ryukyuan languages, though others claim that they are basically different dialects of the Japanese language.There are also other languages (or perhaps just very distinct dialects) spoken in the remote southern parts of Japan
Edited sentence: Linguists believe these should be grouped together as a sub-group to Japonic languages, known as Ryukyuan languages, although many Japanese refer to the speech of these areas as dialects.There are also other languages spoken in the remote southern parts of Japan