@Joeblow,
Quote:NO! You'll just tell me to smarten up.
That's cute.
My son still insists on saying "I seen it." I heard his dad say it the other day.
I suspect that "his dad" is your husband and if I'm correct then I also suspect that 'dad' is about the same age as you, Joe. If he is that, then I know that he knows that the past participle 'seen' needs an auxiliary verb, in this case, 'have', the one you feel is missing.
It has been the trend for at least a hundred years or so for NaE speakers to simplify the use of the present perfect. We now use it, for at least two of its uses, the present perfect of experience [Have you ever skied?] and the present perfect of currentness/importance [I have seen it/I've seen it/I seen it] in quite a different fashion to that of BrE.
For speech, there has always been preference for shortening words; speakers invented contractions. Even BrE speakers use contractions for they're as natural as, well, how can I say this, as natural as speaking.
For the one in question, the present perfect of currentness/importance [I have seen it/I've seen it/I seen it], it has also been that trend for the 'have' to be contracted, then for the contraction to receive less and less aspiration until it is almost voiceless or it is voiceless.
Listen carefully to dad's and son's use. You might notice some differences. Dad's may well be almost voiceless while son's could well be an unvoiced 'have'. It's simply a condition of speech and further, casual speech and even further, youth casual speech.
Your son will grow up to use, ... in fact, I'd bet that even now, he knows the difference between a "I seen it" for casual, excited, rapid speech and an "I've seen it" for more reserved formal situations.
We've all been able to withstand the change from
'have +PP' to
've +PP. It's a small change, and one that isn't always even made, most are just subject to varying degrees of voicing.
Correcting won't make a difference to your son's natural speech patterns, or dad's for that matter. It's like trying to stop them from breathing or showing them a better way to walk.
Blue jeans and T shirts for casual days, ripped blue jeans and a tattered old threadbare T shirt for even more casual days. For the times when it's need, okay, a tux.