It taps the phonological loop, a distinct part of working memory that might otherwise sit idle in non-auditory tasks. More memory is always better, right?
I have always call this “using the air as buffer memory”.
ADDED: Actually it doesn’t just utilise the phonological loop but allows to feed thoughts through a loop than the much longer than intra-brain loops. Longer turn-around-time may allow more complexly interrelated patterns fire up (in response to the spoken word) and stabilize making them available for further introspection.
I have always call this “using the air as buffer memory”.
ADDED: Actually it doesn’t just utilise the phonological loop but allows to feed thoughts through a loop than the much longer than intra-brain loops. Longer turn-around-time may allow more complexly interrelated patterns fire up (in response to the spoken word) and stabilize making them available for further introspection.