Some people with very worn or false teeth can't whistle - the edge of the denture is too rounded to make a good sound against, like the fipple of a penny whistle or a recorder. Conversely, I couldn't whistle through my fingers until I had a false front tooth fitted. The original stuck out somewhat so there was always a gap between them. The falsie is a lot more even and snuggly fitting.

Like I tell Limpit, just keep practising. As soon as she gets the hang of it, she loses another tooth and has to start again!

LTS