说 (traditional 說) has the speech radical 讠 on the left — the same one you met in 谢 (thanks). Speaking is an act of the mouth, so words about talking carry this radical. The right side 兑 gave the sound. 讠 = words coming out; 说 = to SAY them.
说 is everyday Chinese: 说话 (to talk), 你说 (you say / what do you think?), 说不定 (maybe, 'can't say for sure'). 听说 ('hear-say') means 'I heard that...' — pairing the 听 you just learned with 说. Chinese loves stitching simple verbs together like this.
The speech radical (讠) — words coming out of the mouth to SAY something.
听 (listen) + 说 (say) = 听说, 'I heard that...' — literally 'hear-say'. Chinese builds new meanings by simply placing two verbs side by side.