Ancient records suggest that this kind of experiment was carried out from time to time, though the authenticity of these records is unconfirmable. An early record of an experiment of this kind can be found in Herodotus’ Histories. According to Herodotus, after carrying out such an experiment, the Egyptian pharaoh Psamtik I concluded the Phrygian race must predate the Egyptians since the children had first spoken the Phrygian word bekos, meaning “bread.” The children had actually learned the word from the servant who used to feed them.

An alleged experiment carried out by Holy Roman Emperor Frederick II in the 13th century saw young infants raised without human interaction in an attempt to determine if there was a natural language that they might demonstrate once their voices matured. It is claimed he was seeking to discover what language would have been imparted unto Adam and Eve by God.

via Language deprivation experiments – Wikipedia, the free encyclopedia.