TH...the on-going saga

Frunty is working on a "good English" exercise right now on the computer where he has to correct Singlish. He reminded me of what Pit has started to do and it is quite funny. We have been working on correctly pronouncing the "th" sound and now, for some reason, Pit will take any word he feels like and add a "th" where there is not one. For example, Pit will say,

"I hope you feel bether."

It is quite funny but also, ridiculouth. What can you do?!