This advice-column-style blog for SLPs was authored by Pam Marshalla from 2006 to 2015, the archives of which can be explored here. Use the extensive keywords list found in the right-hand column (on mobile: at the bottom of the page) to browse specific topics, or use the search feature to locate specific words or phrases throughout the entire blog.
Q: My colleagues and I are wondering how you go about stimulating elevation of the back of the tongue for [+Back] phonemes?
The very best way to facilitate upward elevation of any part of the tongue, including the back, is to apply a bit of pressure downward at the spot you want to elevate, and to ask the client to push up against your pressure. Use a finger, tongue depressor, Nuk massager, or any other appropriate tool.
This is the process of using RESISTANCE to movement. It means to add a little weight against the direction to which a body part is purposefully moved in order to increase awareness, strength, direction, and control of movement. Resistance is our best tool for facilitating the emergence of new movement.
When done on the back of the tongue, it should set off a gag reflex, so you also may have to utilize techniques to teach the client how to suppress his gag.
Once the client learns how to press upward with pressure against the tongue back, teach him to do so voluntarily without the pressure. He should be able to do it if he has the cognitive level to understand what you are talking about. Then teach him to blow or exhale over the high back position. This will probably sound like a velar fricative or raspberry. Then shape this sound into /k/ or /g/ by making it shorter and shorter.