Comment by thaumasiotes
16 hours ago
Are you claiming that a rhotic "er" exists in American English, or that the British particle "er" is distinct from the British particle "erm"?
> it's usually used instead of "um" to indicate a correction and does sound different
Obviously people can hear the difference between vocalizing with your mouth open and vocalizing with your mouth closed. But there is no systematic difference in use, similarly to how there is no systematic difference in use between "uh-huh" and "mhm".
> Are you claiming that a rhotic "er" exists in American English, or that the British particle "er" is distinct from the British particle "erm"?
Neither. In Amrican English we're fully pronouncing the "r" when we say "er" instead of "um".
> Obviously people can hear the difference between vocalizing with your mouth open and vocalizing with your mouth closed.
That would be "uh" vs "um", not "er".