Lip Syncing

I haven't yet started filming Jacks lip syncing shots but have had an idea of using some of the footage I have filmed to make it seem as if Pippa is lip syncing, at first this proved difficult as she some of the shots where pippa fully opened her mouth weren't close enough for the audience to notice, but I have got footage of pippa sticking her tounge out, the part Pippa will be lip syncing is "toot toot" and "beep beep" I have used two different shots to create the lip syncing and had to change the speed of one of the shots to get her tounge to come out at the right time.