Q: My client and I speak both Spanish and English. He devoices D to make T. I don’t know how to help him.

Here are the things I usually do––

1. Teach him about “Voice-on” and “Voice-off” in a different context. I usually start with “Ah” and “H”.
2. Have him hold his neck at the larynx to feel the vibration of voice on the vowel and the absence of voice on H.
3. Repeat this with the fricative cognates: S and Z, Sh and Zh, F and V, and Th and Th.
4. You are helping him discover that he can turn his voice on for some sounds, and he can turn it off for others.
5. Then apply what he has learned to T and D.
6. Practice with P and B, as well as K and G if he can do those.
7. Train him to listen carefully to all of this. Ultimately it is his ear that must guide him.