How long does it take before dialects branching from a single language become new languages themselves?

Question

In the setting I'm constructing, humans migrated in a single major wave to a pair of large continents within the last thousand years or so (the exact value is partly dependent on the answer to this question). While they initially settled in the coastal regions (as one might expect), over time, the descendants of that original culture have claimed, and sometimes conquered, lands spanning an area roughly equivalent to Europe in size. In the current iteration, cities and nations developed and crumbled and grew again in that time, ultimately resulting in the current, pre-industrial state of the region.

So, the question I've hopefully led up to is this: Supposing that all initial immigrants to this "New World" spoke the same language and shared a largely-similar culture, how long would it take for various subgroups to develop mutually unintelligible languages?

Additional details:

• The region of heaviest colonization and city development is comparable to the Mediterranean in size and shape, so relatively constant sea-based trade and immigration is possible among the major city-states and nations.
• Assume a starting population of approximately 150-200 thousand migrants, with no further migration from the "Old World" (at least nothing appreciable).
• At the onset, the culture has a largely-shared religion, one which has had many aspects more-or-less proven empirically.
• Technology level begins in an approximate Age of Sail, though, the process of this migration is precipitated by a major calamity, so quite a bit of knowledge is lost in transition.
• Magic is not well-suited for long-distance communication of any sort.
• Natives are something of a tricky matter, as there are a couple of categories. Where humans are concerned, the northern continent has a number of tribes (mostly hunter-gatherer, with a handful of legitimate settlements), most of which are north of a number of geographic boundaries that would prove difficult for early exploration. The most accessible regions of the southern continent have a culture of nomads who are relatively cohesive. In both cases, though, all humans are outnumbered significantly by another species/race who only tangentially interact with the other natives, but are capable of verbal communication. At most, there are only a few groups who could be perceived as having anything beyond bronze age technology.

This is my first question here, so please let me know if I need to format this differently, or need to add any further information. Thank y'all!

Answer 1

The answer, strangely enough, is as fast as they want it to. People use language to communicate but also to differentiate. If a group of folks wants to set themselves apart from another group one way to do that is change how they speak. This applies to high-status usages like RP as well as black American English its identical twin Southern American English as well as Cockney, Geordie, or whatever the hell it is they speak in Baltimore. Regional usage becomes a badge of belonging. This even happens in subcultures; Thieves cants, Polari, Hip-Hop lingo, Gobbledygook etc. If you have people who want to set themselves apart from the whole they will play up differences in speech.

Alternately creoles and pidgin these happen very fast a pidgin is what you speak when you date a girl from Guadalajara who thought is was a good idea to learn german and french rather than English. It is a rough and ready mix of whatever works. Grammar from one language a vocabulary based on cognates or strange constructions. "Kerosene-lamp-belong Jesus gone-bugga-up" means "there was a solar eclipse". Creoles are what would have happened if our children would have spoken if it would have worked out between me and Lupe. Creoles are pidgins when they are spoken as native languages they have complete grammars and rules.

If there are native lingos on your world and a chance for creolization combined with nationalism on the part of your subcultures you can really decide on any time scale the story requires. greater than one generation.

now if I can only figure out what "Lo siento, pero usted es demasiado guapo para mí." means.

Answer 2

It really depends quite a lot on the particular environment. The more division the environment provides between people with a dialect, the faster they diverge. This is true for all linguistic studies.

As a real life data point, Kriol from Belize diverged from English in less than 200 years. From the Wikipedia article:

Decker (2005:3)[5] proposes that the creole spoken in Belize previous to 1786 was probably more like Jamaican than the Belize Kriol of today.

This suggests that in 1786, the creole spoken was intelligible by other speakers -- a dialect

A 1987 travel guide in the Chicago Tribune newspaper reported that Belize Kriol is “a language that teases but just escapes the comprehension of a native speaker of English.”

Having been there, I can attest that two native Kriol speakers talking between each other was truly unintelligible to myself.

Answer 3

Here on Earth, Greek is still recognisably the same language as that used by Homer. In contrast English has come into existence in under a thousand years and yet it is far from the newest language on the planet. Why?

A new language, as opposed to a dialect, is most commonly born of the mixing of two peoples with incompatible languages. Incompatible specifically means not dialects of each other. For English its genesis was a mixing of Norman French speaking rulers and Anglo-Saxon languages spoken by the conquered. The pattern is that one generation starts to use a pidgin language to aid communication. The original languages persist in everyday use within linguistically and socially separate communities. The next generation develop the pidgin language into a creole. This evolves rapidly. Words gain new meanings. Clashing grammatical rules get ironed out. As the creole gains expressive power and because everyone is speaking it, the original languages fade away. In subsequent generations the creole evolves very rapidly in its early days. English is still a fast-changing language centuries after Shakespeare, but it is changing nothing like as fast as it did from Chaucer to Shakespeare.

So in your scenario it depends on history. Two isolated groups who started with a common language may drift apart phonetically onto dialects but it will take millennia for these to become more radically different absent the internal pressure created by a cultural merger with another people speaking a truly different language. Where such a merger happens, a new language is virtually guaranteed within three generations. And it has to be a full merger: widespread intermarriage, a coming together as one people or country rather than a land with two peoples speaking different languages who refuse to mix. AFAIK there is no language born of Greek and Turkish, despite the Ottoman empire.

Answer 4

If you have isolation, which includes a lack of things like nationwide radio and publishing, you will have the fastest change and different communities will change in different ways. If something happens to make them want to change, you are still talking a few generations to complete it. If each generation makes small changes, it will take much longer.

So realistically speaking, plan on 3 generations minimum if all the conditions are right.

It can take longer, if there is nationwide communication or standardized education. If teachers are being perscriptive it will hold changes at bay.