How did language spread from one prototype-indo-european language to the more than 6,000 languages we speak today? (100-150) words

As people found themselves unable to communicate, more and more attempts to create a language that a bigger number of people could understand was created. I don't know exactly whom created each language, but its obvious that some groups people found that they were unable to speak one language, so they made their own strictly for the purpose of being able to communicate at a easier way.

(d) it was complex and capable of highly organized efforts.