[vvillena]

The moment that happens, that language would start diverging again. You have to unify culture in order to unify language, and that doesn't sound as good anymore.

Settling on a "common" or "business" language, though, is entirely possible, and has been done many times in history. No language ever encompassed the whole world, and if one language has it's English, right now. Latin, Arabic, Mandarin, French, English, Spanish... The world has seen its share of common languages used within certain spheres of influence.

[mantas]

Point in case - proto Indo European language. It's clear most of European languages (except pre-Indo-European, like Finnish, Estonian, Basque..) have common parent language. For example, look at numbers. All those languages have awfully familiar numbers. If you speak one language, you can recognise most numbers in other languages rather easily. Yet they evolved into very different languages in different regions.

[murukesh_s]

I think numbering system is a recent introduction to European languages - adopted from India in 10th century or so.. but some other words have similarity like maatha- mother, pithaa- father etc!

https://en.m.wikipedia.org/wiki/Hindu–Arabic_numeral_system

[mantas]

Exactly, essential words that we needed thousands of years ago as well as today sound similar. Because they are leftovers from when it was a single language. Modern words that were just invented tend to sound similar as well. E.g. "computer" in different languages. The vast difference is in words that came up in between split of Indo-European tribes and modern times.

[yorwba]

The written numerals are relatively recent, but the words for numbers are much older and still very similar across languages.

[murukesh_s]

Wasn't Roman numerals in use, before the Indo-Arabic came to Europe? How come they are similar? They look worlds apart to me..

https://en.wikipedia.org/wiki/Roman_numerals

[kgwgk]

These are the words the Romans used:

unus duo tres quattor quinque six septem octo novem decem ...

[murukesh_s]

Yes you are right.. indeed sounds similar..

[nl]

The numerals are different but the words are the same. 5 and V are both pronounced “five”, just represented differently.

[murukesh_s]

Ah my bad...