1. Warble: to sing in a sweet, trilling manner (often used for birds)
2. Croon: to sing softly and sweetly, often in a romantic way
3. Hum: to make a low, continuous sound from the throat
4. Chant: to sing repeatedly, usually in a monotone or with a strong rhythm
5. Soar: to sing with power and high notes, reaching for great heights
6. Belt: to sing loudly and powerfully, with strong vocal projection
7. Yowl: to sing in a harsh, loud, and mournful way
8. Cowl: to sing in a low, deep voice, often with a mournful or mysterious tone
9. Trill: to sing with a rapid, alternating series of high and low notes
10. Chirp: to sing in a short, high-pitched sound (often used for birds)
11. Wail: to sing with a long, mournful cry
12. Boogie: to sing in a lively, energetic, and often improvised way
13. Melodize: to sing with a sweet, harmonious voice
14. Rhyme: to sing with words that sound alike
15. Harmonize: to sing in a way that blends with other voices, creating a beautiful sound