鳴ってる

is ringing, is sounding

→ 鳴る

鳴っ ring, sound + て Te-form (conjunctive) + る Progressive/resultative aspect

verb · indicative Rare #37,512

is ringing, is sounding Colloquial contraction of 鳴っている.

JA: 電話が鳴ってる。

EN: The phone is ringing.

Conjugation of 鳴る

Indicative

鳴ってる

Did you hear that thunder?

My phone is ringing.