Language family
A language family was a group of languages that all stemmed from a common root language, as well as the root language itself.
In 2365, Jean-Luc Picard speculated that the Iconian, Dinasian, Dewan, and Iccobar languages were all members of the same language family, which Data agreed might be possible. The android later confirmed this after analyzing the languages. (TNG: "Contagion")