Do the residents of Facade talk in a language that can be understood?

Solution 1:

According to the wiki, the language of Facade residents is an original language, and was derived from the Japanese hiragana (writing system).

A 4Gamer interview revealed that the residents of Facade speak an original language that is meant to be gibberish from scrambled Japanese hiragana. However, the programmer who created the original language program couldn't fix the bugs where it created actual Japanese words. Yoko casually decided that they fit the mood anyway and left them in, causing an accidental misconception that contemporary Japanese still existed in NieR's continuity

The interview (in Japanese) can be found here