There is very little research, practical or otherwise, about the tongue’s characteristics during speech sound productions.
Most typically, we’ve used descriptors such as “place, manner, and voice,” or binary distinctive feature terms which have pretty much fallen from favor. Currently, the terms most often used are phonological processes. While they are excellent at describing speech oral error patterns, they don’t provide much by way of describing desirable speech productions.
As a therapist, I need to know the characteristics of normal speech sound productions. This information helps me analyze the child’s lingual capabilities and tells me what I need to work toward in therapy.
First, I’ll share three research articles that suggest “tongue shapes” that occur during speech production. Then, I’ll share my method for grouping lingual speech sound productions in addition to a few therapy techniques.
Here are the three journal articles:
- Stone and Lundberg’s1996 electropalatography (EPG) study on tongue movements during speech sound production. They categorized tongue shapes into four classes: front raising, complete groove, back raising, and two-point displacement.
- Green and Wang (2003) identified four lingual patterns, also by tongue shapes: Blade elevation with dorsum depression (alveolars, palatoalveolars, the retroflex); body elevation (/j/); dorsum elevation (velars and swallowing), and anterior-blade elevation with body depression (/l/), and
- Stolar and Gick (2013) submitted four tongue surface shapes that occur during speech production. They call them the Lingual Curvature Index.
My Suggestion: A New Way to Group Speech Sound Productions
The three above studies recognize similar lingual grooving (which generates internal stabilization in order to elevate the front-tongue) and lingual elevations (front-tongue elevation and back-tongue elevation). My way of grouping lingual characteristics for speech sound productions was, in part, inspired by these three studies plus several works by Fletcher, and by Gibbons. There are underlying similarities in points of stabilization and mobilization, although they did not always use those terms.
Unlike the three studies that identified lingual surface contours, the following “grouping” is based on lingual planes of movement during speech production.
Do keep in mind that all speech sound productions contain specific lingual- and labial-parts that stabilize, and parts that mobilize. The corners of the lips stabilize (contract) to provide anchorage for the mid-area of the lips to move in a refined, differentiated manner. Regarding a mature jaw, technically it does not anchor in place but the elevator jaw muscles do contract (minimally) to vertically adjust to the needs of the lips and tongue.
Following is a straight-forward and therapeutically helpful way to group English lingual consonant speech sounds; only lingual stabilization and mobilization is addressed.
- Front-tongue Vertical Sounds: /t/, /d/, /n/, /s/, /z/, “sh”, “zh”, “ch”, “j”, /l/, and the retroflex /r/. The tongue braces externally within the upper dental arch and achieves lateral dental/palatal stabilization (placement varies with the individuals palatal vault); it stabilizes internally via the mid-tongue contraction.
- Back-tongue Vertical Sounds: /k/, /g/, /ng/, and the back-up /r/. The “back-tongue corners” brace on the retromolar pads (a dentistry term) behind the top, back teeth while the mid-tongue moves vertically (ever so slightly).
- Mid-tongue Vertical Sound: /j/; the mid-tongue raises and lowers, while the tongue-sides bilaterally brace on the side teeth.
- Whole Tongue Horizontal Sounds: unvoiced “th” and voiced “th”. These two sounds require internal whole-tongue tension while moving horizontally.
Most speech sounds require “vertical” tongue movement; only two speech sounds require “horizontal” tongue movement. Unsure about that? Notice your own tongue’s plane of movement as you move from your tongue’s resting position into the speech sound.
Many of our speech-kids move their tongue horizontally for front-tongue vertical speech sounds. It’s easy to visually determine why they have difficulty producing correct speech movements: Their tongue is not stabilizing appropriately so it can mobilize vertically.
As a precaution, in therapy, when consistent horizontal tongue movement is present (for speech productions that are supposed to be vertical), you may hear a sound that sounds similar to the target. Do know that generalization and transfer will be difficult without appropriate external and internal lingual stabilization. Does this make sense for inter-dental productions? Their tongue is moving horizontally.
A few techniques for generating external lingua-dental bracing/stabilization:
- Check the child’s tongue resting posture. If it’s appropriately up within the dental arch, call attention to the tongue-side touching the top side teeth.
- Again, check the tongue resting position and if it is lowered or low-forward, work on generating appropriate placement. “Wherever the tongue, lips, and jaw rest, is where it works.” The tongue will be more apt to stabilize appropriately for speech sounds if it is consistently rest’s there, i.e., if the tongue-sides contact the top side-teeth at rest.
- Use as many sensations as you can to call attention to the lingua-dental contact:
- Visual: Show them your lingua-dental position. Or, use a big mouth model (by Ajax at Amazon.com) to show the child. Have him/her place his hand inside the mouth model and feel the sides of the teeth with his/her “hand tongue.” Also, use a mirror.
- Auditory: Tell them about the position, and ask them to repeat it back (if possible).
- Tactile: With a tongue depressor (or Nuk Brush) stroke each side of the tongue from back to front as well as the side-perimeter of the palate, and MATCH. Put the two together (the tongue-sides to the side teeth). Do repeatedly until they can focus, feel, and accomplish the placement by themselves.
- Proprioception: Ask them to close their eyes place their tongue in the on-top resting position and focus and feel the tongue-sides on the side teeth/perimeter of the palate.
A few techniques for generating internal mid-tongue contraction/grooving/tongue bowl:
- Generating internal mid-tongue contraction is tricky. Some kids can generate a “tongue bowl” and some kids can’t. Part of the issue is to determine if the child’s tongue is not “bending” because of a lingual tonal issue, or if the tongue is just having difficulty generating and replicating the mid-tongue contraction.
- Show them your tongue bowl in your own mouth. Then, with a child-size tongue depressor, keeping the tongue inside, repeatedly tap the central portion of the tongue while asking the child to tighten that mid-part.
- Sometimes using a Z-Vibe (rather than a tongue depressor) is helpful; vibration has been known to generate muscle contraction.
- Use a spray bottle that has a narrow sprayer. Spray water onto the mid-area of the tongue. Sometimes the tongue will “lower to the occasion” and generate a tongue bowl to hold the water. Do repeatedly.
- Place a small coffee stirrer/straw lengthwise across the tongue-blade. Hold the edges of the straw (with both hands) in place while biting down on the ends of the straw. As you bite, curl the front-tongue up and partially around the straw. Feel the mid-tongue contract.
Go get ‘em! And have a great week!
Thanks sooo much for all you do with your speech kids,
Green, J.R., and Wang, Y. (2003). Tongue-surface movement patterns during speech and swallowing. J Acoust Soc Am, 113 (5),2820-2833.
Stolar, S, and Gick, B. (2013). An index for quantifying tongue curvature. Canadian Acoustics, Vol 41 (1),11-15.
Stone, M., Lundberg, A. (1996). Three-dimensional tongue surface shapes of English consonants and vowels. Journal Acoustic Soc. Am. 99 (6),3728-3737.