cognate

In linguistics, cognates are words that share a common origin or ancestor. This relationship can be seen in words from different languages, such as the English "brother" and the German "Bruder," both tracing back to an ancient root. Similarly, languages like French, Spanish, and Italian are considered cognate because they all evolved from the same ancestral language, Latin.1

The study of cognates is a key part of historical linguistics, where linguists compare related words across languages to reconstruct earlier forms of languages. This involves identifying regular sound changes that have occurred over time. For example, the word for "ten" in Latin (decem), Greek (deka), Sanskrit (daśa), and Gothic (taihun) are cognates, and by comparing their sounds, linguists can reconstruct the likely form of the word in a common ancestor language, such as Proto-Indo-European (dekm). This comparative method helps us understand how languages evolve and relate to one another.2