Is it normal to "lose" things they know (15.5 mos)?

DS is 15.5 mos. For a long time DS had a number of animal sounds and would say them "on command" correctly - if i asked what does the monkey say he would respond, the cow, the sheep and the snake. When he first started doing it (i can't remember exactly when but def. over a month ago maybe 2) we would ask him all the time. then i guess we didn't really ask him much at all. well now, the past week or so he responds with "moo" or "baa" for every sound he used to know! he points to animals that are clearly not cows and says moo so i guess he forgot? this has happened before. When he first learned dog he would always say it and point to the dogs. now he doesn't say dog anymore. It's not like he is regressing b/c he keeps learning new words but its like he forgets or gets the old ones confused Is this the sign of a probem?

Re: Is it normal to "lose" things they know (15.5 mos)?

As long as he's still learning new things, I wouldn't be concerned. I would mention any regression to our Ped. though.

Re: Is it normal to "lose" things they know (15.5 mos)?

At this age they are like sponges and are learning a ton of new things all the time. I would mention it to the ped. but he may just be getting the sounds confused with other animals b/c now is he recognizing more animals, KWIM?

Re: Is it normal to "lose" things they know (15.5 mos)?

A psychologist I work closely with said something that always resonated with me.

Regression doesn't mean losing or forgetting a thing here and there.

Regression happens with a huge chunk of skills - a lot of words, play skills, social skills, etc.

So, animal sounds alone is fine - they will come back. But if it's animal sounds, interactive play, etc - and he used to have it, then that would be a concern!

Re: Is it normal to "lose" things they know (15.5 mos)?

Thanks ladies. I always thought it was normal that he would learn new things and then "forget" them so I'm glad i posted this! I'm going to ask the ped. I feel like there is so much to stress about! On the one hand I am always feeling relieved that he started learning all these things at what seemed like the right times - by 12-13 months he started learning new words and animal sounds daily. But, they all don't stick - some he keeps some he forgets and I'm not sure why.

But thank you for your help! Especially lipglossjunky b/c that is very useful for the future!