A loquacious person talks a lot, often about stuff that only they think is interesting. You can also call them chatty or gabby, but either way, they're loquacious. ... Of course, if you've got nothing to say, a loquacious person might make a good dinner companion, because they'll do all the talking.
Is being loquacious a bad thing?
Loquacious almost always holds a negative connotation, thus making it a more precise word than talkative. A loquacious person is someone who is constantly speaking, often an incessant amount. A loquacious speech, on the other hand, would imply the speech is unnecessarily verbose.
What is wrong with someone who talks all the time?
That said, various forms of excessive talking can show up as a symptom of some mental health conditions: Pressured speech often happens as part of manic or hypomanic episodes. Disorganized speech can show up as a key symptom of schizophrenia and other disorders of psychosis, along with schizotypal personality disorder.