Isoglosses are linguistic boundaries that separate regional dialects and languages. There are various synonyms to describe these language borders, such as linguistic frontiers, language limits, dialect divisions, and speech borders. These synonyms all refer to the areas where different speech forms are in use, marking the boundaries that indicate the regional variations in language use. While the term isogloss is widely used by linguists to describe these boundaries, other phrases like dialectal boundaries or speech differences can also be used. Regardless of the word choice, these different terms all highlight the importance of recognizing distinct language variations and their impact on regional communication.