The words are assigned by a mathematical algorithm. It has placed simpler and more commonly-used words in each language in the areas where the language is spoken. 

The design of our system shuffles word combinations around the world as one of several intentional design features that we balance. The overwhelming proportion of similar-sounding 3 word combinations will be so far apart that an error is obvious, but there will still be cases where potentially confusable word combinations are nearby. Our Autosuggest feature actively intercepts possible errors or confusions and highlights other possibilities to the user, helping to identify what might need to be checked.

This blog explains more about how we handle similar combinations of words.