自じ国こく語ご

noun

one's native language; one's mother tongue

Refers to the language of one's own country; often used in contrast to foreign languages.

• 海かい外がいに住すんでいると、自じ国こく語ごを忘わすれそうになることがある。

  When living abroad, there are times when you feel like you're forgetting your native language.

• 彼かれは自じ国こく語ごのほかに三さんか国こく語ごを話はなせる。

  He can speak three languages besides his mother tongue.