From Old Chinese *m-lod, meaning "to speak" or "to explain." The character 说 (說 in traditional form) combines the semantic component 言 (yán, "speech/words") on the left with the phonetic component 兑 (duì) on the right — a classic form-sound compound (形声字, xíngshēngzì). The same character can be read *yuè* in Classical Chinese meaning "to be pleased," as preserved in the famous opening line of the Analects: 学而时习之，不亦说乎？

说 is one of the highest-frequency verbs in all of Mandarin and appears in dozens of fixed expressions: 说话 (shuōhuà, "to talk"), 听说 (tīngshuō, "to have heard that"), 也就是说 (yě jiùshì shuō, "that is to say"). Be aware that 说 does NOT typically mean "to ask" — a common slip for beginners who reach for it when they mean 问 (wèn). In Cantonese and southern dialects, the equivalent everyday verb is 講 (gǎng/gong), so you may hear that in Hong Kong or Taiwanese contexts.