I thought I'd read somewhere that adding the eee to the end of a word makes it easier for kids to pick up the hard sound? Like, if you say 'Dad', they can't hear the 'd' at the end as well as if you say 'Daddy'.
Considering my son doesn't say anything at all yet, I'll take whatever word he's happy to use to communicate!

We say move between 'ta for mumma' and please and thankyou. He'll pick up on something eventually. He knows what we mean anyway. Trouble with 'ta' is that if he thinks you're saying 'tongue' (first and favourite body part he learned) he'll stick it out and it won't go back in for a long time!