嘴巴
zuǐbā · HSK 4
mouth
👄 嘴 = mouth + 巴 (suffix); 巴 is a common noun-forming particle
嘴 already means mouth; 巴 here is a colloquial suffix that softens it into an everyday word, like adding -y in English. Same 巴 appears in 尾巴 (tail) and 下巴 (chin).
嘴 — mouth 口 + 此 (phonetic) + 角 (horn)
嘴 is a semantic-phonetic compound. The 口 (mouth) component gives the meaning, while 觜 (originally 'beak/horn-tip', combining 此 and 角) supplies the sound. It first meant a bird's beak, then broadened to mean mouth, and by extension the spout or tip of any object.
巴 — single pictograph; itself a radical 巴
Traditionally read as a picture of a large snake: the ancient Shuowen dictionary defines 巴 as a snake said to swallow elephants. It also named the ancient Ba state in present-day Chongqing. Today it means 'cling to' or 'long for' (巴不得), and it is a noun suffix in 尾巴 'tail' and 嘴巴 'mouth'.