Why you should grow tongue muscle fibers using pronunciation tactics or techniques to most efficiently acquire and maintain clear American English speaking.

Understand this: By the time  native-born children are 4 to 5 years old, they typically have a 1,500 to 2,200-word expressive vocabulary (Barnes, 2022).  They pronounce most sounds correctly but may still have trouble with TH, R, S, L, V, CH, SH, and Z.  At 8-years-old, native-born children have mastered all speech sounds as well as rate, pitch and volume and are capable of carrying on a conversation with an adult (Stewart, 2022).    Notice that even for native-borns, the TH and L are not acquired accurately by 4 to 5 year old children who have been talking for 4 years!

Now for the topic at hand. Specific speaking tactics and exercises have speeded up learning and increased accuracy of English speech sounds for our student-learners. How do we know? Not just because we hear that, but because that is measured by assessments.

If you know the “why” you will understand the “how.” 

For skeletal muscles (tongue muscles are skeletal), there are two kinds of muscle fibers, slow twitch muscle fibers and fast twitch muscle fibers.  Scientific evidence indicates average percentage of slow twitch muscle fibers in human tongue is 54% — two-year-olds and adults (Sanders et al 2013).  

Most English consonant and vowel sounds have an extended duration in time, double or more, compared to the quick consonants or vowels.  Additionally, when  the task is to speak clearly,  English talkers do feature enhancement—they extend the duration of speech sounds (the slow consonants and lengthier duration vowels) and  range of articulator movements (which is congruent with the task-dynamic model of speech production—Kelso & Tuller, 1984). 

Getting the long duration English consonants (16 of 24 total consonant sounds) and vowels ( 9 of 14 vowel sounds) and  mastering a different position of articulators for clear easy to perceive English speech sounds is challenging, to say the least,  to the nonnative speaker. That two pronged skill is so critical, we teach it right away.   Of course for some speech sounds, the positioning and speed of  the articulators ( tongue, lips, teeth, jaw, vocal folds/chords) are the same  as for other languages.   It’s where English is different that makes the challenge.

For example TH both voiced and not voiced and L are high error speech sounds for nonnative speakers.

To produce clear, easy to understand  TH  or L speech sounds requires the tongue to be extended forward and for the duration of the speech sound to be extended  for at least double or greater duration in time than a quick English sound such as the consonant sound D.   With the eye, humans can’t see the slow twitch muscle fibers in the tongue.  But it stands to reason that slow twitch muscle fibers are activated to push the tongue blade forward and to extend out or stretch out the tongue blade so the tip extends to the front of the mouth.

To systematize the new learning and to simplify  (and because it works!), we teach the position of the tongue tip for the TH sounds and the L consonant sound to be the same.  That is, push forward  the tip of the tongue so it goes between the upper and lower front teeth or, better yet, to touch the lower lip. 

Consonants TH and L are slow in speed and duration of the speech sound is lengthier than the quick consonants.  The action of pushing the tongue tip all the way to the position of between upper and lower teeth or to touch the lower lip gives sensory feedback to the brain when the target has been reached.  Critically, it takes time— milliseconds— for that tongue action which adds to the duration in time of the TH and L English speech sounds.

Thus you as speaker are taking advantage of biomechanical characteristics of movement of the tongue to extend the duration of the speech sound for the slow consonants TH and L.  It stands to reason that your brain processes the task of pushing your tongue forward to  the lower lip or between top and bottom front teeth  and activates exactly the correct slow twitch muscle fibers.  The central nervous system and the slow twitch muscle fibers must learn this pattern for easy to perceive North American English consonants TH and L.  To make that tongue gesture and movement habitual takes much repeated practice.

Take home message for today, to acquire accurate American English pronunciation requires a tongue forward position for the consonants TH voiced and unvoiced and for L  (and for the American short vowel A).   The same is true for maintaining  the accurate pronunciation for these speech sounds and maintaining the strength of those slow muscle fibers in the tongue needed for these speech sounds.  The key  for acquiring accuracy and maintaining speech sound accuracy is activating the slow muscle fibers to push forward and stretch forward the tongue—that stretching and lengthening the tongue blade not only grows the slow twitch muscle fibers but also biomechanically lengthens the duration of the speech sound when coordinated with voicing at the vocal folds.

Seeing and hearing is understanding.

Below is our speech tip 4 for WORLD— see the pronunciation for L. Hmm, picture says “PAPER.” Unfortunate that YouTube made a mistake for the picture– but click on this YouTube video for WORLD and L. You’ll be glad you did!

Copyright 2022 by Clear Talk Mastery, Inc