Table 3.

Description of the components and features for the articulatory phenotypes.

	Definition	Feature	Parsing and Calculation Methods
Coordination	appropriate temporal alignment of movements to meet task demands	Proportion of Stop Gap to Total Syllable Length	1. Parse each syllable from consonant release (defined by amplitude burst on spectrogram) to subsequent vowel offset (defined by final glottal pulse on spectrogram) and from subsequent vowel offset to subsequent consonant release 2. Calculate duration between vowel offset in /pa/ and release of /t/, between vowel offset in /ta/ and release of /k/, and between vowel offset in /ka/ and release of subsequent /p/ (i.e., gaps during syllable transitions) 3. Calculate duration between release of /p/ to release of /t/, between release of /t/ to release of /k/, and between release of /k/ and release of subsequent /p/ (i.e., full syllable length) 4. Calculate average gap duration and average full syllable length 5. Calculate proportion of average gap duration to average full syllable length
			↑ values = greater gap time during syllable transition and thus ↓ Coordination
Consistency	stability of speech sounds across multiple repetitions	Across-Repetition Variability in Voice Onset Time	1. Parse each consonant from release to subsequent vowel onset (defined by first glottal pulse on spectrogram) 2. Calculate duration between consonant release and subsequent vowel onset for each repetition (i.e., voice onset time [VOT]) 3. Calculate standard deviation in voice onset time between three repetitions and multiply by 100 to obtain coefficient of variation 4. Calculate average standard deviation of VOT across /p/, /t/, and /k/
			↑ values = greater variability in voice onset time and thus ↓ Consistency
Speed	quickness of movement during each syllable repetition	Second Formant Slope of /k/ (Hz/ms)	1. Parse each repetition of /ka/ from vowel onset to vowel offset 2. Run custom Praat script to extract formant time series 3. Divide difference between frequency at vowel midpoint and frequency at vowel onset (i.e., F2-F1) by difference between time at vowel midpoint and time at vowel onset (i.e., T2-T1) for consonant-vowel transition in /ka/ (i.e., F2 slope) 4. Calculate average F2 slope across all three repetitions of /pataka/
			↓ values = reduced rate of vocal tract configuration and thus ↓ Speed
Precision	clearness and distinctiveness of consonants	Across-Consonant Variability in Second Formant Slope	1. Parse each repetition of /pa/, /ta/, and /ka/ from vowel onset to vowel offset 2. Run custom Praat script to extract formant time series 3. Divide F2-F1 by T2-T1 for each consonant-vowel transition in /pa/, /ta/, and /ka/ 4. Calculate standard deviation of F2 slope between consonants within each repetition of /pataka/ 5. Calculate average standard deviation of F2 slope across all three repetitions of /pataka/
			↓ values = reduced variability in place of articulation and thus ↓ Precision
Rate	quickness of completion of syllable sequences	Sequential Motion Rate (syll/sec)	1. Parse first three repetitions from release of first /p/ to vowel offset in third /ka/ 2. Divide duration of three repetitions by nine (i.e., number of syllables produced)
			↓ values = reduced syllables produced per second and thus ↓ Rate