I had my client find different items that 'filter' i.e. colander, towels, things with general holes in them..then we tried to 'filter' things through. What goes through? What stays put?
I then cut out strips of paper and wrote phrases, possibly phrases I have heard her utter in the past, then prompted her with a situation, the phrase and were it should go. BONUS ROUND! She should take the phrase and give an appropriate alternative to stick in the 'mouth' pocket. This practice also provides a great phrase to easily re-direct in the future, i.e "should that stay in our head pocket?"