I can speak/am learning Estonian and there are a lot of words that just don't exist in English.
Thats called lost in translation.
Seriously though, I highly dought that. Technically speaking, the English language has over 600,000 words according to the Oxford dictionary.
It's not all about word count though. It's about the flexibility in being a tool that does a job effectively.
Consider that most European languages have a gender context. So in Polish, you refer to something as a masculine or feminine object I think depending on your own gender or whether the object is considered masculine or feminine.
That's a complexity but like a detail one might find in assembler with an instruciton like MOV:
The instruction is primitive but easy to understand, it effectively moves data around memory but things get complex when you have to learn the various memory addressing modes (registry, memory, indirect, etc).
I would much rather have a named variable assignment, like this:
PHP becomes complex only when the problems you solve become more complex and thus the software becomes more useful or effective as a tool.
Back to the Gender story...it's a detail...that is required but solves an outdated problem. I figure (this I don't know) that gender context exists because at one time, men and women were not seen as equals. There could be other evolutionary reasons behind that, like maybe men and women all looked the same in caveman days and to avoid picking up a man at the local bar, they used gender context to distinguish female cavemen from male cavemen. Hahaha.

Just kidding.
Anyways, the detail is not needed and as English evolved from other European languages, that detail was dropped and focus was put on solving other issues, such as eliminating extraneous words by introducing context, such as my
"Where, were, ware, we're"
Do such words exist in other languages? I'm not sure but it solves the problem of having to introduce a new word each time something crops up. The basic makeup of English and how we construct sentances, our grammar and syntax are extremely well done and clearly evolved from other languages, which technically, does it make it better for the job of communicating.
I get the feeling you both feel like I have insulted the cultural aspect of language and that is not my intent, but technically English does it best. Obviously arts and culture are undefinable, you cannot standardize them then life would be boring and innovation would seize to exist.
It is much easier to express yourself in Estonian in writing than it is in English
How is it easier? Again, it's not about word count (but I'm willing to bet that English has the largest dictionary) it's also about how those words are constructed and how flexible sentances can be when constructed.
I never used to read novels, but recently I have been, just for the simple fact that language fascinates me. I now realize how unique and different each author's writing style is. Some people are excellent communicators and others can get an idea across for the life of them.
I am willing to bet as well that same diversity doesn't exist in novels outside of English. Sure they might be different styles but not as vast as English.
Put it this way...I can probably pick out (without seeing member names) arborint, maugrim, chris, everah, feyd, onion2k, pickle, etc...all from just reading their message because each individual has such a unique approach to communicating (thanks to the flexibility English offers). Could you do the same in Estonian or any other langauge? It'd be an interesting test or challenge to qualify as to what language was indeed the winner -- technically speaking.
And for english to be difficult to learn, try learning Estonian or Russian or Chinese then talk to me about a difficult language.
No language is "easy" to learn...lets face it...even Latin is not easy and it hasn't been in common use for centuries probably.
English at a basic level I am willing to bet is easier to learn. The way in which you construct a sentance has rules but those (grammar) are flexibile enough that even a poorly constructed sentance makes sense. I've lived with and around immigrants (of every culture) my whole life this so this I do know.
The rules that dictate sentance or paragraph construction are what are technnically superior in English. It (the language) has the benefit of evolution and learning from past experiences. Silly rules were probably dropped and new ones introduced.
Again I would put money on the fact that Esontian has more senseless caveats than English -- to actually catch though you have to think really abstract or outside of the box, draw on similar analogies and most importantly put your pride aside an be willing to accept the truth.
That and, as pytrin said, the cultural/financial influence America and the UK have had has helped spread the language around the world.
I'm not denying that USA and UK helped the spread of English. But why then does it spread so well? If it flopped or there was something better, then naturally that language would eventually take its place. Will something replace English, like Chinese? I dought it, not in our life time.
Homosapiens have been around for something like 50k years...in that time we've slowly evolved. I think English was simply the last langauge to develop, inherited the best practices and such from other Indo-European languages and voila. There is little need for any new langauge to evolve (I dought Klingon will replace it very much) as English solves all the problems very well.
Perhaps when we as a species begin to colonize the moon or mars a new English dialect will surface but the basic rules or grammar will stay the same. Perhaps some might get dropped as we change our approach to communicating, like if we begin reading minds and no long need to communicate verbally.