Cooperation among peoples is greatly enhanced by language, though this is not the only vehicle for communication possible. The statement that a picture is worth a thousand words can scarcely be argued. Nevertheless, humans who do not speak the same language essentially do not associate with each other, they avoid each other and segregation results. Nevertheless there are common threads in all languages, based on words that mock natural sounds and developmental associations the child makes. Early races of man, developing in isolation from each other, did not develop common languages, and this situation persists today. In fact, isolation creates different languages that started from the same base. They grow apart.
The legend of the Tower of Babel reflects this common occurrence, but the legend is not altogether fancy. Deliberate separation occurred in mankind's recent past, among groups that were commandeered into forced labor by the hominoid visitors from the 12th Planet. These slave-masters were constantly on the alert to prevent their slaves from gaining their technological advantages. The visitors constructed towers, silos in fact, to surround the missiles they used to shuttle between Earth and their home planet when it made a periodic appearance. When groups of their slave-laborers were found snooping and sharing information with each other, they were separated, forcibly. What remained of the story was the tower, the clustering of man, and the resulting separation due to language barriers. They did not separate because of a language barrier, the barrier developed because of separation.