Lesson 17, Exercise 8:
Voluble, loquacious, talkative, and chatty are synonyms

The main meaning of the verb 'chat' is to talk. The adjective 'chatty' is based on the verb!
 
Voluble is a less common word than talkative for talking a lot, which is what we see here: lots and lots of talking by both people in conversations.

Voluble people are always talking.

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