Excitement level in OCEAN model
It sounds like an aspect of extraversion. I.e., loud and fast talking sounds like gregariousness and assertiveness.  In general, extraverts are also more active and expressive.
For example, the NEO-PI-R has facets of extraversion as follows:
(E1) Warmth (E2)
Gregariousness (E3) Assertiveness (E4) Activity (E5)
Excitement-Seeking (E6) Positive Emotions
Fast talking might also be linked to intelligence.