Not to start an angel "slide" here,
(if there is such a thing.)
Isaiah 6, one of my favorite.
>>>If not sing, speak, chant, or intone. What's the diff?
There is a clear difference between singing and talking. That difference has always been quite distinct, unless one has a hearing disability, in which case, I'd totally understand the confusion.
Little baby-faced, or effeminate angels wearing a little cloth, strumming on a harp, are purely the invention of painters and sculptors like Michelangelo and DaVinci though.
Biblical angels are a bit different than poetry and fiction.
Psalm 34:7
"For the angel of the LORD is a guard; he surrounds and defends all who fear him."