Having Word Trouble

kanela13

Our almost 4 year old has some trouble with words what end with "S" and turns them into words that end with "ED", has anyone else gone through this? Here are some examples of the words he uses: bookeds - books; cateds - cats; these are the only ones I can think of at the moment. I don't correct him and make him say it correctly, I just repeat back to him the correct word, but I'm wondering if anyone else's child does or has done this.  I'll be asking his pedi when we go for his 4YO check up to see if it's any concern.