singing — to utter words or sounds in succession with musical modulations of the voice; vocalize melodically.
song — Ailing [ahy-ling] /ˈaɪˈlɪŋ/ (Show IPA), Soong, Ai-ling.
adjective warbling
whistling — an instrument for producing whistling sounds by means of the breath, steam, etc., as a small wooden or tin tube, a pipe, or a similar device with an air chamber containing a small ball that oscillates when air is forced through an opening, producing a high-pitched, warbling tone.
