"The Japanese language doesn't belong to any group of languages and doesn't have any connections to any other languages."
"Japanese isn't related to any other languages."
- "The Japanese language doesn't belong to any group of languages and doesn't have any connections to any other languages."
"the Japanese language" 「日本語」
"doesn't belong to" 「〜に属さない」
"group of languages" 「言語のグループ」
"doesn't have any connections to~" 「〜に関係がない」・「仲間外れ」
- "Japanese isn't related to any other languages." 「日本語には言語の仲間がいない」