呢喃 (ní nán) — (noun) the twittering or chirping of swallows; (noun) a soft murmur, whisper, or muttering (of a person)

Definition

Examples

• 春天来了，燕子在屋檐下呢喃。
  Chūn tiān lái le, yàn zi zài wū yán xià ní nán.
  Spring has come, and the swallows are twittering under the eaves.
• 她坐在窗边，嘴里不停地呢喃着什么。
  Tā zuò zài chuāng biān, zuǐ lǐ bù tíng dì ní nán zhe shén me.
  She sat by the window, softly murmuring something to herself.
• 风声中夹杂着燕子的呢喃，十分动听。
  Fēng shēng zhōng jiā zá zhe yàn zi de ní nán, shí fēn dòng tīng.
  The wind carries the twittering of swallows — it's very pleasant to hear.