They're old words. For example yesterday he was trying to say something was on the couch and he got stuck on 'on' and finally gave up after 9 tries and just pointed to it. He's 3.5.Sometimes it's normal. When I was little and I didn't know how to pronounce things I would do that. Are they new words or old? And how old is he? My youngest son had to go to speech therapy because he couldn't say the hard "r" sound for awhile, mostly because when he was little his brother and sister would speak for him a lot instead of letting him speak.