warble
[verb]
Synonyms: sing, chirp, trill, twitter

[TahlilGaran] English Synonym Dictionary ▲

war‧ble /ˈwɔːbəl $ ˈwɔːr-/ verb
[Date: 1300-1400; Language: Old North French; Origin: werbler]

1. [intransitive] to sing with a high continuous but quickly changing sound, the way a bird does

2. [intransitive and transitive] to sing, especially not very well – used humorously:
Mills warbled a few notes.
—warble noun [countable]

[TahlilGaran] Dictionary of Contemporary English ▲