誰に教わった

who did you learn from?

→ 誰
phrase Rare #44,130
who did you learn from? 教わる means to learn from or be taught by someone. The subject is often omitted and understood from context.
JA: この料理、誰に教わったの?
EN: Who did you learn to make this dish from?

そいつはスゴイな誰に教わったんだ?

That's amazing! Who taught you that?

— ジョジョ・ラビット (2019)

誰に教わったんだこれ

Who taught you this?

— 万引き家族 (2018)

誰に教わった?

Who taught you?

— 預言者 (2009)