warble
US /ˈwɔːr.bəl/
UK /ˈwɔːr.bəl/

1.
gazouiller, chanter
to sing in a soft, low voice, especially with a trilling or quavering sound
:
•
The bird began to warble a sweet melody.
L'oiseau commença à gazouiller une douce mélodie.
•
She would often warble old folk songs.
Elle avait l'habitude de chanter de vieilles chansons folkloriques.
1.