Cognates

Cognates are words in two or more languages that descend from a common ancestral word. They typically retain similarities in form and meaning that reflect historical connections between languages. Cognates are central to historical and comparative linguistics because they help reconstruct older stages of language and illuminate regular patterns of sound change and semantic shift across language families.

Cognates are most common among closely related languages, such as the Germanic languages (English, German, Dutch, Swedish) or the Romance languages (Latin, Spanish, French). They originate in a shared ancestor, such as Proto-Germanic or Proto-Indo-European. Regular sound correspondences across languages allow linguists to group cognates into sets and to infer the form of the parent word.

Not every similar word is a cognate. False friends or false cognates resemble each other but differ in meaning due to semantic drift. Borrowings—words adopted from other languages after their separation—are not true cognates, even if they look familiar. Distinguishing cognates from these cases requires historical evidence and etymological analysis.

Examples include English mother and German Mutter; night, Dutch nacht and German Nacht; water and German Wasser and Dutch water; father and German Vater and Dutch vader; brother and German Bruder. These pairs show how a single ancestor word can diversify across languages while remaining recognizable.

Cognates underpin language classification and the reconstruction of proto-languages. They are also helpful in vocabulary learning, comparative dictionaries, and understanding historical contact between languages.