Most likely you began (and continued) to use the word I to distinguish yourself from other selves, and you to distinguish another self (singular or collective) with whom you are engaged in joint attention from other things, any of which could be the object of your joint attention (i.e. could be referred to in the third person).
You might imagine the other with whom you are thus coupled, and you might believe that the person you are addressing as ‘you’ is only imaginary. But it is highly implausible that you could have learned to use language (or any medium of communication) in that belief; what motive could you have for learning it? Besides, if you believe that you are not even possibly addressing a real person – not even your future self – then surely you don’t believe that your expression signifies anything. How can you be a real sign if you don’t mean something to somebody?
Hence the Creator’s need for projecting creations into independency before drawing them into harmony.