Singsong (noun)

1. A continuous, monotonous repetition of words or sounds, typically in a sing-song tone of voice.
2. A song or melody that is characterized by a repetitive or monotonous quality.
3. A playful or teasing tone of voice.

Origin:

The origin of the word singsong is uncertain, but it is believed to have originated in the late 16th century and is likely derived from the middle english word singesong.

Examples:

1. The child's singsong voice was so soothing that it helped the baby fall asleep.
2. The singsong of the birds outside the window was a pleasant background noise.
3. She spoke in a singsong voice, as if she were reciting a nursery rhyme.
4. The old man hummed a singsong tune as he worked in his garden.
5. She spoke in a singsong voice, full of sarcasm.