expression, ichidan verb
reveal one's poor upbringing; betray one's origin; give oneself away
Used when someone's behavior, speech, or manners unintentionally show a lack of refinement or a humble background. Often carries a critical or mocking tone.
彼は言葉遣いでお里が知れる。
His way of speaking reveals his poor upbringing.
テーブルマナーを見れば、お里
You can tell someone's background by their table manners.