The word 发音 is formed by combining two individual characters, each contributing a core meaning to create a new, composite concept. The first character, 发 (fā), carries the fundamental idea of "sending out" or "emitting". The second character, 音 (yīn), solely means "sound". When placed together, their meanings fuse in a direct, logical sequence: 发 acts upon 音, resulting in the combined sense of "to emit sound", which specifically refers to the act of pronunciation.