My 2.5 year old repeats everything almost that we say. He knows A for apple to Z for zoo and 1-50. He can also recite few rhymes like baa baa black sheep and johny johny. But he doesn't converse with us. all he talks to us is either numbers or lines of the rhymes he knows. is this normal in this age? he rarely calls us mumma papa, but identifies us in photos as mumma papa. Please let me know if this is normal