Context: By the definition most commonly used by linguists, any linguistic variety can be considered a "dialect" of some language—"everybody speaks a dialect". According to that interpretation, the criteria above merely serve to distinguish whether two varieties are dialects of the same language or dialects of different languages.

Question: According to most linguistics, who speaks a dialect?
Answer: everybody

Question: What do only a few linguists believe people speak?
Answer: Unanswerable

Question: According to the least used definition, what does everyone speak?
Answer: Unanswerable

Question: What are used to distinguish between two varieties of different languages only?
Answer: Unanswerable

Question: What does the criteria believe everybody speaks?
Answer: Unanswerable