Interesting, I often sing a good night lullaby to my kid and have discovered it’s trivial to read while doing so. But I just tried talking while counting in my head and it felt like a brick wall was blocking me.
I remember a story about people who stutter not stuttering while singing.
“Everybody's sayin' that the Scatman stutters
But doesn't ever stutter when he sings
But what you don't know, I'm gonna tell you right now
That the stutter and the scat is the same thing”