Clear Talk Mode and the Task-dynamic Model of Speech Production

Why read this?   It’s for people who are a little intense about getting the best out of learning.

Does the nature of the speaking task, like the nature of the movement task, change the dynamics of the system?

Did you ever do running in a race?    Did you do a sprint—50 or 100 meters or yards?   Or long distance?  Then you know that  act of running changes the tenseness of muscles, the rate, and rhythm  of movement compared to walking.  Those features of the muscle actions are also different for sprint (relatively short distance “as fast as you can”) compared to long distance or marathon running. This is called the task-dynamic model  (Kelso and Tuller, 1984, Saltzman et al, 2010) and hierarchical task-based control model of speech incorporating sensory feedback by Parrell, B. et al. (2018).

For human speaking, these task-dynamic modes are called registers or speaking styles , or speaking modes.  One speaking style or mode is  “motherese” or the speaking pattern mothers all over the word use when talking to young children.  What do you hear in “motherese” – higher pitch, emphasizing words by going up in pitch, emphasized sounds and movement of the articulators—lips, tongue, jaw, teeth.

Other modes in English have been  investigated  beginning in the 1920s and summarized by Denes and Pinson (1993) and later studies also summarized by  Smiljanic and Bradlow (2009). These research investigations included  the effect of the  range of sound intensity (loudness) on intelligibility , the effect for intelligibility when talking over background noise, the features of English speech when the task is to talk clearly to persons who have a hearing impairment, and the style called Clear Speech.   Very limited study has also been reported by Smiljanic and Bradlow for the style Clear Speech for other languages or Clear Speech style of talking in English for non-native speakers of American English (AE).  In 2000, Antonia Johnson published her dissertation which compared a   Clear Speech prescribed mode or style of speaking to conversational style in non-native speakers of English.

Briefly, research study determined that features of  clear speech in English includes greater speech volume (louder), feature enhancement for consonants (e.g. making fricatives like S, SH, F, V, TH lengthier in duration), feature enhancement for vowels ( e.g. using greater opening of the mouth for the first part of  long vowels A, I, and O,  and extending the duration time for the English short vowels A and O and changing of formant frequencies and change for vowels).

Since 2000, we at Clear Talk Mastery have scientifically analyzed assessment for almost a thousand different people with  63 different languages and from  64 countries for intelligibility (pre diagnostic assessments, mid-course and end of course assessments).

The task for our student-learners has been  to acquire clear English speech—to increase intelligibility or understandability of their American English speech. Johnson discovered in the dissertation work that in order to go into the clear speaking AE mode and learn the six strategies which native-born speakers of American English use when speaking clearly, non-native born speakers of English needed more.  They required specific enunciation instruction—what features of the 23 consonants and 14 vowel sounds to enhance,  precisely where to position the articulators of tongue, lips, teeth, jaw, instruction on making articulator muscles stiff and tense, which speech sounds to lengthen in duration and which to produce quickly.  These we called Tactics (Tactics are details for strategies.)

Notably, the task-dynamic model was our important guide— the task was for student-learners to acquire a clear speaking mode which made  AE (American English) highly understandable to all listeners (native born English speakers and non-native speakers of English).

A sidebar:  Based on the speed of being able to use strategies of clear speaking derived from previous and our own research, we have concluded that all languages have  a clear speaking mode— probably used at a minimum when talking in noisy environments from childhood or perhaps talking to a person with a hearing impairment (like a grandparent) when the purpose of the speaking task was to be understood.  For example, who hasn’t noticed a toddler aged 18 months up to age 4 requesting an item from the mom or caretaker when in a noisy room? 

We found that the style of clear talking or Clear Talking Mode when first learned— along with specific enunciation instructions—produced a predictable mode or style of speaking.   Student-learners reported using high energy, high attention when first learning the Clear Talk Strategies with the added enunciation instructions (including Tactics).   The features of this mode when speaking in a sentence included pauses between the words (and syllables) as the talker was processing in the brain the “plan” for the next word and a quick review in the brain of the accuracy of the previous word.  Our instruction for AE speech sounds including for learning purposes to hyperarticulate the consonants so they were at least double loud and double slow (for lengthier duration consonants) and double fast (for quick AE) consonants.  The rationale for this hyperarticulation was that the brain learns faster when the movement or action is highly salient—easy to feel and hear.

Accurate vowel pronunciation for 14 AE vowels was instructed after “mastery” of consonants (about 80-90%) using the clear speaking mode.  For home practice, to speed up learning, student-learners used maximum effort, maximum accuracy of positioning of the articulators, hyper or very enhanced feature of prolonging appropriate AE consonants and maximum tensing the articulator muscles.  By 2017, our observations during instruction and assessments made it clear that this learning mode has unique characteristics so we gave it a name – we called this Workout Practice, or Workout Mode of Clear Talk.  There is more to be said on this, which I will get to later.

Importantly, we emphasized that in daily life  when talking with other people, the optimal Clear Talk Mode or style of talking would be a mode where the articulator muscles continued to be stiff and tense but not maximal tenseness and the pauses between words not as lengthy.   This mode or style we called Careful Clear Talk Mode.   Because muscles and the brain or central nervous system were learning a new series of patterns (procedural learning), it was impossible for student-learners to make the change quickly in speech gestures of the consonant- to- vowel -to consonant speech sounds in a word.  For example for the word “tag”, to  push the tongue to the roof or top of the mouth hard and quickly for the T consonant then push tongue forward (and flat) for the AE short vowel A, then raise the back of the tongue blade to the roof of the mouth at the back of the mouth for a  G consonant  — these series of speech gestures  were impossible for nonnative speakers to do as quickly as an adult native speaker of English or a child because native speakers of AE  had literally years of practice.  In other words, it was impossible for the non-native learner to imitate the speed of a native-born adult AE speaker. 

Based on much research, including our own Action Research (ongoing assessment which directed change in instruction), we adhered to the Task-Dynamic Model  of  human movement and speech production.  It was a mode we were instructing—much like a physical trainer would instruct a runner eager to succeed in long distance running.

Like other physical activities, speech is central nervous system (brain and nerves) and muscles.  Just as there is the Task-Dynamic and Hierarchical Task-Dynamic model for Motor Control (motor means movement), there is also a Task-Dynamic Model for Speech Production.

For efficacious clear AE speech instruction,  we used diagnostic pre assessment,  mid-course and post course assessment.   More on this later.

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