Backward-Speaking Boy

Noah has been talking for a long time, he has a big vocabulary, puts sentences together well, and often times surprises me in using proper grammar in situations where most adults wouldn't. He is funny about some of his word sets though, and he says them backward. I think it is cute/funny, and at this point am not worried about it, as he's only three and still learning language skills, and he does not confuse sets of words that are similar or always confuse/say backward the ones listed below.

Here are a few sets of words that he typically (but not always) says backward:
"Mow lawn" = Lawn mower
"Wack weeder" = Weed wacker
"Wash car" = Car wash

Funny boy!