I have written two tongue twisters:

WHAT SAUL SHORNE SAW
Sitting on a see-saw Saul Shorne saw Shawn Shaw saw. The sawing Saul Shorne saw Shawn Shaw do was surely strange as Shawn Shaw sawed the see-saw Saul Shorne was on. Saul Shorne was so sore Shawn Shaw sawed the see-saw he saw to it that Shawn Shaw sawed the see-saw no more. So instead of a saw Shawn Shaw used an axe.

CONFUSED
It was with that that was with this, this was with that that was. Was that with this, that that was this or that ? No - its that that that was with this that and that that this was not just that.

Choose some other homonyms or initial sounds and make up your own tortous tongue twisters. for more tongue twisters see Rosen, M. (selected) (1997). Walking The Bridge Of Your Nose. KIngfished Publications.