I am trying to understand the principles how a proto language produces it daughter languages, do they proliferate from dialects of the same proto language or do they proliferate from dialects of other daughter languages?

E.g. Are English, German, Dutch and Icelandic all originally dialects of Proto-German or are they dialects of another daughter language. Does this actually happen where a daughter becomes the proto for another set of languages? (like Italian seems to descend from Latin but Italian itself seems to be a proto language for later Italian languages?

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    It's best to look at that process from the point of view of communities of people: if a community splits, each of the resulting new communities tends to develop its own dialect, and the further those communities get separated, the more divergent their dialects become. There can be zillions of variants of how it can happen, and since most languages got separated from one another centuries and millennia ago, little can be known of the minute details of their factions, dialectal affiliation, and interactions among those closely related communities. It could be any way.
    – Yellow Sky
    Commented Aug 31, 2021 at 20:33
  • This is how I imagine it too. If you begin with source A say its splits its A1, A2 and A3, then A1 into A1A1, A2 into A2A1 and A3 into A3A1, and then A1A1 into A1A1A1, A1A1A2 etc like the haplogroups in genetics. Is the same happening with languages then? Here I am confused. Commented Aug 31, 2021 at 20:41
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    Language evolution is indeed not unlike genetic evolution. The difficulty that linguists encounter is that written language is relatively recent, so we don't have "fossils" of early languages. The best they can do is hypothesize what the "proto" languages were like.
    – Barmar
    Commented Sep 1, 2021 at 14:49
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    All of these questions are fine, you just need to read the textbook I've already recommended several times, Lyle Campbell, Historical Linguistics: An introduction (2020, 4th ed.), published by Edinburgh UP (in the UK) and MIT (in the US). Chapter 9. Language classification and models of language change.
    – Alex B.
    Commented Sep 1, 2021 at 15:59
  • Both. Proto-Germanic itself can be considered the ancestor of Proto-Norse, which is the ancestor of Icelandic, Swedish, Norwegian, etc, but not of English, modern German, or Dutch. (Though yes, I am aware of various degrees of opinion on how much influence Proto-Norse and its offshoots may have had on the development of English.)
    – chepner
    Commented Sep 2, 2021 at 14:08

2 Answers 2


A proto-language is a hypothesis - it's a theory about the history of a language family. A proto-language is a model of the closest common ancestor of the daughter languages, but which is not directly attested itself (ie, we don't have anything written in it.) So neither Latin nor Italian are proto-languages, because we have direct written evidence of both. Proto-Germanic and Proto-Indo-European are models of languages we think were spoken at one time, but which were never written down.

user6726's answer is a good explanation of the tree model of linguistic families. Many language families can be effectively explained through the tree model. But you should also be aware that there are some changes in languages which cannot be accounted for through simple descent as in the tree model. Some changes are introduced from neighbouring languages; these are called areal features. The wave model of linguistic families goes further and says that most changes spread as areal features rather than strictly through descent in a splitting family tree.


The theory is that there is a community, whose members speak "a language" (one language). They go about life, roaming the plains of whatever, and their children learn that language. As long as they remain a coherent community whose members are in contact with one another, everybody speaks the same language. The language might change a bit, but it changes for everybody. But sometimes one group of people head off somewhere else, and have little to no contact with their cousins. Languages change all the time, but when you have a single community whose members are in contact, the change tends to be in the same direction. Once you put a mountain or other obstacle between two communities, the speech of one group can become substantially different from the speech of the other group. Initially, that might be called (by linguists) a difference of "dialect", but with enough time and change, you have different languages. The "proto-language" is the language as it was spoken by a single community, and the "descendant languages" that are used to reconstruct the proto-language are the languages that you actually encounter.

Obviously, contact and social influence are not an all or nothing proposition. Suppose that humans shipped 10,000 people to colonize a planet in another galaxy. Even if everybody used English, not everybody in this community would speak the same dialect of English. Some would be from California, some from New York, some from South Africa (and so on), and some would be second-language speakers from France or Mongolia. One or two Mongolian speakers would probably not have a substantial impact on the resulting language 2,000 years after, but if the Mongolian community were 1/3 of the population, there is a fair change that that would have an influence on later languages. There would already exist dialects of English, and distinctions could be passed on depending on whether your ancestors were from the Mongolian-influenced dialect vs. the California-influenced dialect. Hence the assumption that "Proto-Indo-European" or some other language was originally completely homogenous is likely to be false.

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    Thanks. So can this lead to a language chain then where there is an original proto language and then a dialect breaks of and becomes another language and then another dialect breaks off that it and becomes another language and so on? If yes, then how do you get back to the first proto from the newest split of languages? Finally, when a dialect splits off aren't the dialects going to all have different sound changes? Commented Aug 31, 2021 at 20:55
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    @LinguistEnthusiast It's a bit more complex than that - while yes, in general there's a notion of a "family tree" of languages, in practice every language borrows from its neighbours (English being a prominent example). There's also areas of the family tree that are wholly unknown, or only beginning to be explored - for instance, there is no clear consensus as to what language(s) Japanese evolved from. Commented Sep 1, 2021 at 7:57
  • I was going to pithily comment on how, as we all originate from somewhere in the African continent, neat it is that the Inuit have many words for snow, and some African languages may have none, and after researching, I was mislead as a child. (They only have two, one for (the act) of snowing and one for (the physical) snow, itself. Bummer.
    – CGCampbell
    Commented Sep 1, 2021 at 15:59

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