Surely, apart from the overall effect which is going to be a personal thing, it is about voice.

Voiced consonants can be sung compare the fricatives "v" & "f" with your hand on your larynx and see what I mean. Explosives like "p" and "b" are less recognisable if elongated but it is not true of all consonants like "v" or liquids like "l".

IMHO it is the phonemes that tell you. That and the audience!!!!!