Which word characterizes someone who is excessively talkative?

The term "loquacious" specifically describes someone who is very talkative, often to an excessive degree. It emphasizes a tendency to talk freely and a propensity for verbosity, making it distinct from other words that might imply mere willingness to communicate or share information.

"Verbose" also relates to excessive wordiness, but it is often used to describe writing or speech that is unnecessarily lengthy or complicated, rather than characterizing a person specifically.

"Reticent" conveys the opposite sentiment, indicating someone who is reserved or reluctant to speak, which contrasts starkly with the meaning of being excessively talkative.

"Communicative" suggests a general willingness to engage in conversation, but does not inherently convey the excessive aspect of talkativeness, making it a broader term that doesn't capture the same specific trait.

Thus, "loquacious" is the most fitting choice for characterizing someone who tends to be excessively talkative.