Q: My client only produces [+Back] consonants K and G, and he sucks his thumb. His tongue is beginning to move for L. Do you think that the thumb sucking is keeping his tongue retracted?

Tongue retraction can have many causes including an oral habit like thumb sucking. It also can be the result of oral-tactile hypersensitivity that is causing the tongue to pull back and high in a perpetual “high guard” position. It also is a problem when oral muscle tone is too high. It also can be a simply habit.

From a speech motor perspective, the anterior sounds P, B, M, W, T, D, N, and L come in when the jaw begins to move up-and-down. Therefore babies begin to babble primarily with [+Anterior] consonants because the jaw begins to oscillate up-and-down. The up-and-down jaw movement pattern causes the lower lip to bang upward against the upper lip, and it causes the anterior tongue to bang upward against the upper lip and gums (or teeth if the child has any). This movement pattern emerges between 4-6 months of age when the jaw also begins to oscillate up-and-down in spoon-feeding.

A child who produces no [+Anterior] consonants and who principally backs his consonants may not have activated the jaw’s basic up-down oscillating movement pattern. The thumb may be preventing the pattern from emerging if it is in the mouth much of the day and/or night. The thumb acts to hold the jaw and anterior tongue in a low position. This can prevent both the jaw and the tongue from becoming active for the anterior consonants.

Whether the thumb is the cause of the lack of anterior phonemes in this case is uncertain. This depends on how often and for how long the thumb is in the mouth. I would want to find out if the client keeps the thumb in the mouth for five minutes at a time, or for hours at a time, when he is awake. At night I would want to know if the child sucks his thumb only for a few minutes to fall asleep, or if he sucks it off-and-on throughout the entire night. We need to know about frequency and duration of thumb sucking.

My preference would be to help the family understand that the thumb sucking must go. Although we have no “proof” in the laboratory sense that thumb sucking causes problems with the emergence of anterior phonemes, we certainly can say that it might be for this child. The only way to know if thumb sucking is affecting the child’s speech is to eliminate it. My book called How to Stop Thumbsucking has many ideas about how to go about this. Another book on this topic by Rosemary Van Norman also is good. [Van Norman, R. (1999) Help for the Thumb-Sucking Child. NY: Avery]

In terms of stimulating the anterior phonemes, my preference would be to stimulate all of them in babbling sequences and words with “Ah” without trying to stimulate any one in particular. In other words, I like to cause the [+Anterior] feature to emerge first. I worry about the particular phoneme second.

Simple CV and CV-CV words would be my preference. For example:

• CV: pah (pop), bah (bye), Mah (mom), Wah (water), Tah (hot), Dah (dad), la (singing sound), na (no)

• CV-CV: pah-pah (grandpa), bah-bah (bye-bye or bottle), Mah-mah (momma), wah-wah (water), tah-tah (bye-bye), dah-dah (dada), lah-lah (the yellow Telletubby or the word “yellow”), nah-nah (grandma, nanny, no-no)

• CV-CV in the diminutive form: doggie, kitty, birdie, horsie, mommy, daddy, baby, nanny, blankie (blanket), etc.

As I stimulate emergence of these sounds, I make sure the child is producing them with big up-and-down jaw movements, and I don’t worry about what the lips or tongue are doing. The jaw has to do this work first. I stimulate for appropriate lip and tongue movements only after the sounds emerge with the big jaw movements.

I also would teach the lingua-alveolars T, D, N, L in babbling sequences with the tongue OUTSIDE the mouth at first so that the anterior portion of the tongue is banged upward against the upper lip and teeth. This will “awaken” the anterior portion of the tongue. Bring it inside the mouth later, only after the [+Anterior] phonemes begin to emerge.

I also would be providing some oral-tactile experiences to awaken the lips and anterior tongue.