Why is it you're here with いんの

Grammar Explanation: Contracting いる＋の to いんの

Aru returns to her classroom after club. Expecting the classroom to be empty, she’s singing a song about herself as she enters the room. There, she finds her friends idling away the time.

アル:: 「なな　何(なん)で皆(みな)いんのよ！（誰(だれ)もいないと思(おも)ってた！）」; "Wh- why is it that you all are here?! (I was thinking no one was here!)"
なこ:: 「（なんだ今(いま)の歌(うた)…）」; "(What was with that song just now...)"
ソトカ:: 「師匠(ししょう)がアルを待(ま)つって」; "Master said she'd wait for you."
アル:: 「でも私(わたし)部活(ぶかつ)あるわよ」; "But I'm in a club!"

Note: Sotoka refers to Bocchi as 師匠(ししょう).

Why is it you're here with いんの

See also