A language family is a grouping of linguistically linked languages, stemming from a common ancestral mother-language called Protolanguage.
Most languages in the world belong to a specific family. Languages that have no demonstrable relation with others, and cannot be classified within a specific family, are generally known as language isolates.
Creole languages are the only ones to be neither isolates, nor members of a linguistic family. They form their own different type of languages.
If we compare, for instance, French, Spanish, Portuguese, Italian, Romanian, we discover a surprising set of resemblances, which give to these languages a “family likeness”. This “family likeness” does not appear when comparing French to German. But if one compares German to English, Dutch, Swedish or Danish, one finds another “family likeness” between these languages.
The basic idea is that those languages look alike because all of them are different evolutions, “descendants” from a same former language (also called “protolanguage”), which does not exist anymore. We know the common origin (Latin) of the five languages we mentioned first, called romance languages whereas we don’t have any written documents in the former language of the four languages we referred to after, called Germanic languages, but we can reasonably think that it existed. Linguists manage to set up genetic classifications by comparing languages and trying to define constant rules about their similarities (and differences). This method is called comparative linguistics. The classification of languages in groups of languages is called genetic classification: two languages belonging to the same group are genetically linked.
However, one has to pay attention. Resemblances between two or several languages may come from their genetic relationship (resembling shapes come from a common former shape) but they also may have others origins:
– loans : the fact that the French word tomate looks like the Aztec word tomatl does not prove that these two languages are connected, but rather that they have been in contact. The name given to a new plant brought to Europe was the name people from its homeland had given it. Therefore, French “borrowed” a word from another language and adapted it to its vocabulary.
– random : languages have limited sounds systems to express thousands of complex notions. If we choose randomly two languages spoken far away one from another, we always find 3 or 4 words that look alike, in their shape and meaning.
Therefore, one can speak about a genetic relationship only if one finds a converging set of resemblances, even partial, instead of a striking but isolated resemblance.
Many families, large families
As ” sister ” languages exist, coming from a common language spoken 1000 or 2000 years ago, one can imagine ”cousin” languages coming from older languages. In the 19th century, by highlighting systematic and convergent similarities, some linguists showed the existence of a large Indo-European family, the first linguistic family to be identified, which includes Romance languages, Germanic languages, Slavonic languages, Greek and others (see the page about the Indo-European family). And if the similarities between French and Russian surprise you, try to compare French to Nepali, or Pachtoun to Kurdish! Nevertheless, they are Indo-European languages. To belong to the same family does not guarantee an obvious similarity, nor a standard level of comprehension between the speakers of these languages.
Indo-European example list