
national language
Japanese language (esp. as a school subject in Japan)
one's native language; mother tongue
native Japanese words (as opposed to loanwords and Chinese-derived words)
国語辞典で漢字の読み方を調べた。
I looked up kanji readings in a Japanese dictionary.
国語の授業が一番好きだったな。
I liked Japanese class the most.
小学生の頃は国語が一番好きな教科だった。
When I was in elementary school, Japanese was my favorite subject.