哪儿的话 / 哪里哪里【nǎr de huà / nǎli nǎli】

哪里哪里 is the modest answer to a compliment: "oh, not really", "you're too kind". 哪里 means "where", and the reply works like asking where the praise could have come from. It is said twice.

It is polite but a little old-fashioned. Younger speakers often say 过奖了 "you flatter me", or simply 谢谢.

哪儿的话 for thanks and apologies too

哪儿的话 (or 哪里的话) means "what are you saying" – nothing to praise, thank or apologise for. It covers more ground than 哪里哪里, and often leads into a reason.

Which one where

哪里哪里 answers praise only. To a thank-you, use 不客气 or 哪儿的话.

• × 谢谢你帮我！哪里哪里。 → 谢谢你帮我！不客气。
• × 你真聪明！哪里。 → 你真聪明！哪里哪里。

A single 哪里 in reply to praise reads as a question, "where?". Say it twice.