It seems to me it is more interesting to build a continuum based on how much of their true core self people are willing to share in all contexts. Someone willing to share all in all contexts is socially open. Someone unwilling or unable to ever share is closed.
Talking a lot does not mean someone actually like people, or is interacting with them honestly.
Conversely, not feeling the need to speak does not betray timidity or “introversion.”
Many people we label introverts are simply uncomfortable both with being emotionally dishonest and superficial, on the one hand, and being reliably misunderstood by silly people on the other. This says nothing about their latent capacities, only what they learned from repeated experience.