Two questions about language evolution (primarily PIE and proto-nostratic)

Question

Okay, so a little background information:

Recently I've been thinking about how quite a few languages (talking mostly about IE languages here) appear to be 'simplifying' themselves over time, getting rid of cases and simplifying their conjugation systems. Obviously, these languages aren't truly 'simplifying' themselves. There is no doubt that Latin's case system, for example, is obviously more complex than, say, English's, but does that make English's grammar less complex? Where older IE languages like Latin and old English used inflection to convey meaning, modern languages like English and Italian use syntax and other means of doing so. These languages aren't 'simplifying' themselves, just becoming less synthetic and more analytical, it's not about complexity here.

But the trend is still undoubtedly there, modern IE languages are -as a general pattern- becoming more analytical, like how Italian has no cases, Latin had five, Proto-Italic is reconstructed to have seven, PIE probably had eight, and if PIE had a predecessor, perhaps something like Proto-Nostratic, a theory which might be on to something, but it would definitely be difficult to reconstruct such an old proto language beyond a handful of roots and some very basic grammar, that predecessor would have been even more analytical, possibly something even like Turkish or Finnish. So, here are my questions:

a) If the farther back we go, the more morphologically complex these languages get, then how would have such a complex languages arisen in the first place? How did early humans go from a few strings of sounds to denote objects or even actions, to eventually be speaking in an elaborately inflected language so easily? I know this evolution would have taken place over literally millions of years, and that we will probably never know for certain, but if there is some thought up explanation I would like to hear it.

b) Why is it that so many languages are becoming less synthetic over time? Is it because of some change in people themselves? Or are more analytical languages just 'lazier'? It doesn't make sense that they just would. There has to be some reason I have failed to think of. It doesn't make sense that synthetic languages are simply less efficient, because then why would they appear in the first place? Has there been any research on this that I am unaware of? Then I would definitely like to see it.

Answer 1

(a) If there were a clear trend from flexive type to analytical type, over the last 100,000 years or so, it would follow that almost all the languages of the world would have evolved to be analytic languages (which does not seem to be the case). Therefore, it is possible that there are processes that remorphologize languages. I am not saying that there is a cyclical process, as I know a researcher who found that there are some irreversible trends, which have been growing as the world population went from 10 million (late Paleolithic) to almost 8 billion today. So I consider that in the matter of the existence of morphological flexion there are fluctuations whereby it sometimes decreases and sometimes increases.

(b) This is not clear, but the changes in the Neolithic settlements caused people who spoke different languages to concentrate in larger political organizations, in fact, the work I mention by my colleague showed that it was near the areas where agriculture emerged that there were greater tendencies towards a specific type. However, it is not clear what the specific mechanism would be, by which languages change in the presence of speakers of different languages.

Answer 2

First of all, the immediate predecessor of PIE was probably Proto-Indo-Uralic, then something like Proto-Eurasiatic, while Proto-Nostratic is more hypothetical than not.

So, we can look at Uralic languages in an attempt to grasp what do they have in common with PIE that could be an inherited trait.

And what we see? The most of Uralic languages are agglutinative.

Indeed, it is usually assumed that language development is cyclic: analytic->agglutinative->fusional-> analytic.

What does it mean? In an analytic language like English or Chinese, the meanings of the words are conducted with service words, like modal verbs, articles, proverbs and prepositions. In the second stage of development, those service words are attached to the roots and stems so to become morphemes. In the third stage, those morphemes fuse together so that a morpheme conducts not only one meaning like case or number, but the both, case and number at the same time (for instance). And then the cycle repeats, the complicated morphemes get dropped, and this process is accelerated especially with creolization, when non-native speakers start to speak the language.

Even in PIE we see that the most morphemes, like suffixes or prefixes at that stage still had structure, similar to the roots. They had usually one vowel in various ablaut grades, like suffixes -ter-/-tor-/-tr-, -iea̯-/-ia̯- or -is-/-ios-/-ies-. The endings also had ablaut grades.

Moreover, the prefixes in PIE were mostly adverb-prepositions in shortened ablaut grade. semi → sm-, a̯enti → a̯nt-, peri → pro-, a̯epi → a̯po-, e̯eni → e̯n-, e̯neu → e̯nu-, etc.

More to this, PIE was great at concatenation of the roots into one word, and it is often impossible to tell if the word is just a two-root word or a root with some suffix/prefix. Is dusdius ("bad-sky", thunder) a prefix+root or two roots? What about sma̯eḱsia̯ ("one-axis", carriot)? What about ḱleupa̯ter ("famous-father")?