Post History

What drives the complexity of a language?

Looking at English, its complexity seems to have been in constant decrease. For example, in the past, there were conjugations and a separate informal form of “you” (”thou”); all in all, the language was much closer to German. On the other hand, German still has those complexities; however as far as I can tell, it certainly has not gained any new ones (except for the current gender issues).

Also looking at Romance languages, as far as I can tell there has been complexity loss. While Latin has three genders, as far as I can tell all modern Romance languages have only two. And I don't think any of them has the complete six-case declination of Latin.

So all in all, it looks as if the complexity of a language has the general trend to go down over time. But that cannot be the case: Complex languages like Latin or Greek didn't just pop up in their finished form, but developed from earlier languages, and at some time in the past, those languages would need to have been much simpler; it is inconceivable that the first languages humanity developed were extremely complex.

Therefore there must be times when language gets more complex (up to the high complexities of Latin and Greek), and other times when it gets simpler. And those changes surely don't just happen at random.

One guess would be that complexity is added when society changes a lot, but certainly modern technology changed the society quite a bit, but it doesn't seem to drive the language to more complexity. There are more words invented, but not more grammar, as far as I can tell.

So what does actually drive this complexity? That is, what determines whether a language gets more complex or simpler over time?