There are many reasons, in my experience. Often because they are just nervous, or naturally chatty and outgoing. Unfortunately there are some people who consider themselves to be more important and talk over others. Also people with anxiety disorders do it because they are agitated.
Jabber jaw, verbose, talkaholic, motor mouth , , ,
garrulous, voluble
umm by phone or if the question is meant to be (waht do you call a person with a lot of money) that answer is rich
contrary
A narcoleptic person; a person with narcolepsy.
That would be either forgetful or absentminded.
Outspoken?
A person who speaks a lot is often referred to as talkative or loquacious.
talkative
A person who speaks many languages is often called a polyglot.
A person who speaks clearly is often referred to as articulate or eloquent.
That would be a disciple.
eugoogalizer
A person who speaks a lot can be described as talkative, chatty, or loquacious.
A person who speaks out against something is often referred to as a critic, dissenter, or opponent.
A person who speaks and understands many languages can be called a polyglot.
That would be a disciple.
a linguist
Pretentious.