when stroke victims have damage to broca's area, their speech is effected, but many times they can still sing, .. they sometimes ...can summon up bits of songs, melodies and words, and begin ... communication.
Stutterers can often sing clearly with no impediments on certain consonants .... now, wait a sec ... do people who stutter have trouble just with consonants? Never heard of anyone's having trouble with vowels (a, e, i, o, u)
Years ago there was a joke that gained wide currency about a stuttering sailor who had to sing about a man falling overboard for the Captain to understand. The punch line had to be sung for full impact!
Anyone remember it?