Everybody on this thread took literally my wish of "one language" but I never would've said C++ would be replaced by Java, for example. So I really meant "one language" in each category. Obviously there has to be a language to generate machine code, and then another higher-level language on top of that, and so forth.
The world is better off with fewer rather than more languages for obvious reasons. I never really considered the industry to be a fragmented mess until "Go" and "Rust" came along. That was the straw on the camels back for me where I just said: "Ok please stop, you aren't helping."
I have just used one language professionally, but do you think having just one language can solve the problem? But, I agree if a language has all the features you need, and is mainstream, you are well off using that than jumping in for another language for the heck of it and reinventing wheel is not helping anybody.
I am repeating myself, but different people might have different working style. And have different communities have different taste and ways of doing stuff.
Language is not the only barrier in communication. It is just one parameter. I honestly think, different languages allows different ways of doing things (not better), with different tradeoffs. My preference to some language is not just about language I know, but also with respect to what I want to do. And how I want to do solve the problem at hand.
Even if a language, supports all possible styles of programming, will that result in a coherent language? Then, might the language be language not get very big that different people working in different styles resulting either in monstrosity of code base or fragmentation in language community. Else, the language itself might not represent the problems succinctly as the user wants. Features are not the only issue here.
If the language is just needles and redundant, there is not going to be difference in its absence. Yet, I have seen people who have very strong opinions on how to organize code, OOP or not OOP, and of course tabs vs spaces. The fragmentation is inevitable and going to exist as long as strong opinions exist.
The best analogy I can think of to make the point of how important the 'single language syntax' goal should be is "mathematics".
Imagine if everyone "doing" math did it their own way, using their own sets of symbols, and syntax. Even Einstein got his Special Theory of Relativity transform directly from Lorentz. Most innovations are built on top of other innovations, and the ability to share depends on common language.
Not to refute your point here, but I consider improvements in the way the language lets you express your thoughts is also very important. But, I get what you are saying.
Consider an extreme straw man example of roman numeral system winning over everything just because of the inertia. The decimal system is great innovation because, it gave us succinct way expressing idea of numbers.
Not all languages are like that, but certain languages allow and encourage certain style of programming like OOP for java, though it is a multi paradigm language. I think inertia plays a big role here too. Java is always going to be OOPy language for the most part, because it is what community is built on.
Most problems in trying to understanding and communicating is going to be about concepts not the language. The syntax is probably some work, but half a day of work. But, I often do not find it hard to read the code in some other language, I get it once I see the code. But, even after seeing some code, I find it hard to come with code in that language. Because, that is the hard part. jq is one such language. Even though it is niche. When after reading docs, I find it so hard to combine all the small parts of it to make sufficiently large program. That will take, however similar the syntax is.
That is the reason, some particular style of programming dominating a language community. We got settle on something. Language is geared towards solving problems and introducing features for certain style. And that helps. It gives a coherent outlook to language and the community.
That is what I mean when I say, fragmentation is inevitable. Not everybody wants to understand all different ways of doing things. Even if the concepts seem understandable, thinking in terms of them is much harder for people. Multiple language for different dominant style seems to be a saner alternative than single language with all the different style.
The world is better off with fewer rather than more languages for obvious reasons. I never really considered the industry to be a fragmented mess until "Go" and "Rust" came along. That was the straw on the camels back for me where I just said: "Ok please stop, you aren't helping."