https://en.wikipedia.org/wiki/Language_deprivation_experiments
Mughal emperor Akbar was later said to have children raised by mute wetnurses. Akbar held that speech arose from hearing; thus children raised without hearing human speech would become mute.[9] The building became known as the "dumb house." When Akbar visited the place in 1582, four years after the children were first interred, he heard "no cry... nor any speech... no talisman of speech, and nothing came out except the noise of the dumb."[10]
Akbar's study is most likely authentic, but offers an ambiguous outcome.[11]