The paper analyzes the vocabulary of the Tsakonian dialect of Modern Greek and refutes the hypothesis about its isolation from other Greek idioms. The material reveals some similarities with the Northern Greek dialectal vocabulary, which allows us to conclude that the aforementioned dialects have been circulating in a common geographic area. Tsakonian vocabulary demonstrates almost the same foreign borrowings as other Modem Greek dialects, whereas Ancient Greek roots and neologisms provide its lexical uniqueness. The Tsakonian dialect is incomprehensible for speakers of Standard Modem Greek due to its phonetics and morphology, but not its lexical peculiarities.