Whenever we compare two forms of speech - two dialects of a single language, two related languages, or even any two languages chosen at random – we encounter some words which are similar in sound and in meaning. This double similarity may be due to [...] direct inheritance in both forms of speech from an earlier form of speech which was the common ancestor of the two. In the third case, we call the words ‘cognates’.
- Hockett (1958), a pag.486