Warble (verb)

1. To sing or make musical sounds with a trilling or vibrating quality.
2. To produce a high-pitched unsteady sound.

Origin:

The word "warble" has been in use since the 16th century and comes from the old english word "wærblian" which means "to sing with trills or variations." it is derived from the germanic base "wærbl-", meaning "to sing" and "-ian" meaning "to make or do".

Examples:

1. The bird warbled a beautiful melody in the morning.
2. He warbled a tune as he worked in the garden.
3. The warbling of the stream was soothing to the ear.
4. The engine began to warble, signaling that it needed repairs.
5. The warbling of the singer's voice was a sign of her nervousness.