What term refers to someone who is reserved and speaks very little?

The term that describes someone who is reserved and speaks very little is "taciturn." This word characterizes individuals who tend to be quiet and uncommunicative, often speaking only when necessary. The origin of "taciturn" comes from the Latin "tacere," which means "to be silent." This trait can be associated with a thoughtful demeanor or a preference for listening over speaking.

The other terms provided indicate the opposite of being taciturn. "Talkative," "loquacious," and "chatty" all describe people who are inclined to talk a lot and engage in conversations, contrasting sharply with the reserved nature implied by "taciturn." Thus, in the context of the question, "taciturn" is the accurate description of someone who speaks very little.