Pronunciation of "Three"

With my Yr 5 students, I've lately been teaching them to count to 20. With the Yr 6 students, I've been teaching them to count to 100. Either way, we end up with the pronunciation of the th sound, in either three or thirty.

While not being a Nazi on the subject, I am making sure to spend a bit of time explaining how to make the th sound, as I firmly believe that the younger they learn it, the easier it will be. My favourite routine involves poking my tounge out at the kids, waggling my hands up near my ears, and then encouraging them to do the same back at me. They're usually a bit shy, hesitant, and giggly, but a few will do it, and then most of the others will jump on board. Once most of them have their tounges poked out at me, I explain that to make the th sound, they need to have their tounge between their teeth.

This has had results. On their feedback sheets at the end of the lesson, I have had a significant number of children say that they now understand the pronunciation of three. Unfortunately, many of them still insist on using katakanna to show that they now understand the pronunciation, so I have ended up with a number of variations on "I used to think it was suri but now I know its shuri/turi/furi" with the odd kid who actually uses the roman script to show th. They do actually (mostly) get the pronunciation, it's just that their script is completely inadequate for representing it!