The Divine Source
In most religions, it is believed that language is a God-given gift to human species. In Christianity, God gave Adam the kingdom of all animals in the Garden of Eden and the first thing Adam did was to name these animals. That is how language started according to religious sources. Today people speak many different languages rather than only one language because ancient humans became too proud and they tried to build the Tower of Babel in order to reach God. So, God punished them by separating their languages.
People tried to discover the original divine language which was spoken by our most ancient ancestors. They assumed that if a child was brought up without hearing any language, the first word the child would utter would be in this divine language.