Abstract
Purpose:
This study investigated native Cantonese-speaking preschool children's diadochokinetic performance, including rate, accuracy, and regularity. The second aim of this study was to examine whether language-specific patterns exist by comparing diadochokinetic rates with the average DKK rate for native English speakers.
Method:
Sixty-four typically developing preschool children who were native Cantonese speakers participated. The diadochokinetic task administered to the children involved repetitions of monosyllabic, disyllabic, and trisyllabic words and nonsense words. The maximum performance of the children was compared by diadochokinetic rate (number of syllables per second), accuracy (percentage of matched production), and regularity (pairwise variability indexes, known as PVIs).
Results:
Monosyllabic units were produced faster, more accurately, and more regularly than multisyllabic units. Word repetition showed higher accuracy and generally lower regularity than nonsense words but similar rates. Older children were faster and more regular (higher raw PVI of initial consonants) than younger children, but younger children performed as accurately as them. When compared with data from English speakers, the diadochokinetic rates of Cantonese children were generally lower.
Conclusions:
Developmental progression was evident in terms of rate and regularity. The distinctive accuracy and regularity patterns between word and nonsense word repetition suggest a clinical value for both stimulus types. Language typology plays a role in diadochokinetic rate, supporting the use of language-specific reference data in practice. The typical diadochokinetic profile obtained in this study could serve as a clinical reference for speech motor assessments.
References
-
Ackermann, H., Hertrich, I., & Hehr, T. (1995). Oral diadochokinesis in neurological dysarthrias.Folia Phoniatrica et Logopaedica, 47(1), 15–23. https://doi.org/10.1159/000266338 -
Alshahwan, M. I., Cowell, P. E., & Whiteside, S. P. (2020). Diadochokinetic rate in Saudi and Bahraini Arabic speakers: Dialect and the influence of syllable type.Saudi Journal of Biological Sciences, 27(1), 303–308. https://doi.org/10.1016/j.sjbs.2019.09.021 - American Speech-Language-Hearing Association. (2007). Childhood apraxia of speech.Retrived July 2, 2019, from https://www.asha.org/policy/TR2007-00278/
-
Baayen, R. H., Davidson, D. J., & Bates, D. M. (2008). Mixed-effects modeling with crossed random effects for subjects and items.Journal of Memory and Language, 59(4), 390–412. https://doi.org/10.1016/j.jml.2007.12.005 -
Ben-David, B. M., & Icht, M. (2017). Oral-diadochokinetic rates for Hebrew-speaking healthy ageing population: Non-word versus real-word repetition.International Journal of Language & Communication Disorders, 52(3), 301–310. https://doi.org/10.1111/1460-6984.12272 -
Bhat, J. S. (2012). Oral diadokokinetic rate—An insight into speech motor control.International Journal of Advanced Speech and Hearing Research, 1(1), 10–14. -
Bigi, B. (2015). SPPAS-multi-lingual approaches to the automatic annotation of speech.Journal of the International Society of Phonetic Sciences, 111, 54–69. -
Bigi, B . (2016, December 7–9). A phonetization approach for the forced-alignment task in SPPAS[Paper presentation] .LTC 2013: Human Language Technology. Challenges for Computer Science and Linguistics , Cham, Switzerland. https://doi.org/10.1007/978-3-319-43808-5_30 -
Boersma, P. P. G., & Weenink, D. J. M. (2020). Praat: Doing phonetics by computer(Version 6.1.11) [Computer software] . http://www.praat.org/ -
Bouvier, L., Monetta, L., Laforce, R. J., Vitali, P., Bocti, C., & Martel-Sauvageau, V. (2021). Progressive apraxia of speech in Quebec French speakers: A case series.International Journal of Language & Communication Disorders, 56(3), 528–548. https://doi.org/10.1111/1460-6984.12606 -
Brosseau-Lapré, F., & Rvachew, S. (2018). Introduction to speech sound disorders. Plural. -
Canning, B., & Rose, M. (1974). Clinical measurements of the speed of tongue and lip movements in British children with normal speech.British Journal of Disorders of Communication, 9(1), 45–50. https://doi.org/10.3109/13682827409011607 -
Cheung, P. S. P., Ng, A., & To, C. K. S. (2006). Hong Kong `Cantonese Articulation Test.Language Information Sciences Research Centre, City University of Hong Kong, Hong Kong. -
Cho, T., & Ladefoged, P. (1999). Variation and universals in VOT: Evidence from 18 languages.Journal of Phonetics, 27(2), 207–229. https://doi.org/10.1006/jpho.1999.0094 -
Chow, I., Brown, S., Poon, M., & Weishaar, K. (2010, May 11–14). A musical template for phrasal rhythm in spoken Cantonese[Paper presentation] .Speech Prosody 2010 , Chicago, IL. -
Cohen, W., & Waters, D. (1999, August 1–7). Measuring speech motor skills in normally developing and phonologically disordered pre-school children[Paper presentation] .Proceedings of the XIVth International Congress of Phonetic Sciences , San Francisco, CA, United States. -
Cohen, W., Waters, D., & Hewlett, N. (1998). DDK rates in the paediatric clinic: A methodological minefield.International Journal of Language & Communication Disorders, 33(S1), 428–433. https://doi.org/10.3109/13682829809179463 -
Craik, K. J. (1947). Theory of the human opertator in control systems 1. The operator as an engineering system.British Journal of Psychology, 38(2), 56–61. https://doi.org/10.1111/j.2044-8295.1947.tb01141.x -
Craik, K. J. (1948). Theory of the human operator in control systems II. Man as an element in a control system.British Journal of Psychology, 38(3), 142–148. https://doi.org/10.1111/j.2044-8295.1948.tb01149.x -
Davis, B. L., Jakielski, K. J., & Marquardt, T. P. (1998). Developmental apraxia of speech: Determiners of differential diagnosis.Clinical Linguistics & Phonetics, 12(1), 25–45. https://doi.org/10.3109/02699209808985211 -
De Jong, K., Beckman, M. E., & Edwards, J. (1993). The interplay between prosodic structure and coarticulation.Language and Speech, 36(2–3), 197–212. https://doi.org/10.1177/002383099303600305 -
Deterding, D. (2001). The measurement of rhythm: A comparison of Singapore and British English.Journal of Phonetics, 29(2), 217–230. https://doi.org/10.1006/jpho.2001.0138 -
Diepeveen, S., vanHaaften, L., Terband, H., De Swart, B., & Maassen, B. (2019). A standardized protocol for maximum repetition rate assessment in children.Folia Phoniatrica et Logopaedica, 71(5–6), 238–250. https://doi.org/10.1159/000500305 -
Diepeveen, S., vanHaaften, L., Terband, H., deSwart, B., & Maassen, B. (2020). Clinical reasoning for speech sound disorders: Diagnosis and intervention in speech-language pathologists' daily practice.American Journal of Speech-Language Pathology, 29(3), 1529–1549. https://doi.org/10.1044/2020_AJSLP-19-00040 -
Dinnsen, D. A., Chin, S. B., Elbert, M., & Powell, T. W. (1990). Some constraints on functionally disordered phonologies: Phonetic inventories and phonotactics.Journal of Speech, Language, and Hearing Research, 33(1), 28–37. https://doi.org/10.1044/jshr.3301.28 -
Dodd, B., Zhu, H., Crosbie, S., Holm, A., & Ozanne, A. (2002). Diagnostic Evaluation of Articulation and Phonology (DEAP). Psychology Corporation. -
Dollaghan, C., & Campbell, T. F. (1998). Nonword repetition and child language impairment.Journal of Speech, Language, and Hearing Research, 41(5), 1136–1146. https://doi.org/10.1044/jslhr.4105.1136 -
Duchin, S. W., & Mysak, E. D. (1987). Disfluency and rate characteristics of young adult, middle-aged, and older males.Journal of Communication Disorders, 20(3), 245–257. https://doi.org/10.1016/0021-9924(87)90022-0 -
Duffy, J. R. (2020). Motor speech disorders: Substrates, differential diagnosis, and management (4th ed.). Elsevier Health Sciences. -
Dworkin, J. P., Aronson, A. E., & Mulder, D. W. (1980). Tongue force in normals and in dysarthric patients with amyotrophic lateral sclerosis.Journal of Speech and Hearing Research, 23(4), 828–837. https://doi.org/10.1044/jshr.2304.828 -
Fletcher, S. G. (1972). Time-by-count measurement of diadochokinetic syllable rate.Journal of Speech and Hearing Research, 15(4), 763–770. https://doi.org/10.1044/jshr.1504.763 -
Franich, K., Wong, H. Y., Yu, A. C. L., & To, C. K. S. (2020). Temporal coordination and prosodic structure in autism spectrum disorder: Timing across speech and non-speech motor domains.Journal of Autism and Developmental Disorders, 51(8), 2929–2949. https://doi.org/10.1007/s10803-020-04758-z -
Gibbon, D., & Williams, B. (2007, August 6–10). Timing patterns in Welsh[Paper presentation] .Proceedings of the International Congress of Phonetic Sciences , Saarbrücken, Germany. -
Grabe, E., & Low, E. L. (2002). Durational variability in speech and the rhythm class hypothesis.Papers in Laboratory Phonology, 7(1982), 515–546. https://doi.org/10.1515/9783110197105.2.515 - 102(3), 594–621. https://doi.org/10.1037/0033-295X.102.3.594
-
Guenther, F.H. (2016). Neural control of speech. MIT Press. https://doi.org/10.7551/mitpress/10471.001.0001 -
Henry, C. E. (1990). The development of oral diadochokinesia and non-linguistic rhythmic skills in normal and speech-disordered young children.Clinical Linguistics & Phonetics, 4(2), 121–137. https://doi.org/10.3109/02699209008985476 -
Hurkmans, J., Jonkers, R., Boonstra, A. M., Stewart, R. E., & Reinders-Messelink, H. A. (2012). Assessing the treatment effects in apraxia of speech: Introduction and evaluation of the Modified Diadochokinesis Test.International Journal of Language & Communication Disorders, 47(4), 427–436. https://doi.org/10.1111/j.1460-6984.2012.00155.x -
Icht, M., & Ben-David, B. M. (2014). Oral-diadochokinesis rates across languages: English and Hebrew norms.Journal of Communication Disorders, 48(5), 27–37. https://doi.org/10.1016/j.jcomdis.2014.02.002 -
Icht, M., & Ben-David, B. M. (2021). Evaluating rate and accuracy of real word vs. non-word diadochokinetic productions from childhood to early adulthood in Hebrew speakers.Journal of Communication Disorders, 92, 106112. https://doi.org/10.1016/j.jcomdis.2021.106112 -
Jang, J., Choe, Y. G., & Ha, S. (2021). Characteristics of diadochokinesis in typically developing children and adults.Audiology and Speech Research, 17(1), 73–80. https://doi.org/10.21848/asr.200072 -
Jordan, L. S., Hardy, J. C., & Morris, H. L. (1978). Performance of children with good and poor articulation on tasks of tongue placement.Journal of Speech and Hearing Research, 21(3), 429–439. https://doi.org/10.1044/jshr.2103.429 -
Kent, R. D. (1992). The biology of phonological development.In C. A. Ferguson, L. Menn, & C. Stoel-Gammon (Eds.), Phonological development: Models, research, implications, (pp. 65–90). York Press. -
Kent, R. D. (2015). Nonspeech oral movements and oral motor disorders: A narrative review.American Journal of Speech-Language Pathology, 24(4), 763–789. https://doi.org/10.1044/2015_AJSLP-14-0179 -
Kent, R. D., & Forner, L. L. (1980). Speech segment durations in sentence recitations by children and adults.Journal of Phonetics, 8(2), 157–168. https://doi.org/10.1016/S0095-4470(19)31460-3 -
Kent, R. D., Kent, J. F., & Rosenbek, J. C. (1987). Maximum performance tests of speech production.Journal of Speech and Hearing Disorders, 52(4), 367–387. https://doi.org/10.1044/jshd.5204.367 -
Kent, R. D., Kim, Y., & Chen, L. M. (2022). Oral and laryngeal diadochokinesis across the life span: A scoping review of methods, reference data, and clinical applications.Journal of Speech, Language, and Hearing Research, 65(2), 574–623. https://doi.org/10.1044/2021_JSLHR-21-00396 -
Kirby, J., & Yu, A. (2007). Lexical and phonotactic effects on wordlikeness judgments in Cantonese. In Proceedings of the 16th International Congress of Phonetic Sciences: ICPhS XVI.(pp. 1389–1392). -
Kok, E. C. E., & To, C. K. (2019). Revisiting the cutoff criteria of Intelligibility in Context Scale–Traditional Chinese. Language, Speech, and Hearing Services in Schools. 50(4), 629–638. https://doi.org/10.1044/2019_LSHSS-18-0073 -
Krishnan, G. (2016). Assessment of rate and consistency in performance of diadochokinetic task in children and adults using an automated assessment protocol: A preliminary study.Asian Journal of Multidisciplinary Studies, 4(8). -
Lau, J. C. Y., Patel, S., Kang, X., Nayar, K., Martin, G. E., Choy, J., Wong, P. C. M., & Losh, M. (2022). Cross-linguistic patterns of speech prosodic differences in autism: A machine learning study.PLOS ONE, 17(6), Article e0269637. https://doi.org/10.1371/journal.pone.0269637 -
Law, T., Packman, A., Onslow, M., To, C. K. S., Tong, M. C. F., & Lee, K. Y. S. (2018). Rhythmic speech and stuttering reduction in a syllable-timed language.Clinical Linguistics & Phonetics, 32(10), 932–949. https://doi.org/10.1080/02699206.2018.1480655 -
Lee, K. Y. S., Lee, L. W. T., & Cheung, P. S. P. (1996). Hong Kong Cantonese Receptive Vocabulary Test. Hong Kong Society for Child Health and Development. -
Lee, S., Potamianos, A., & Narayanan, S. (1999). Acoustics of children's speech: Developmental changes of temporal and spectral parameters.The Journal of the Acoustical Society of America, 105(3), 1455–1468. https://doi.org/10.1121/1.426686 -
Lehiste, I. (1970). Suprasegmentals. MIT Press. -
Low, E. L. (1998). Prosodic prominence in Singapore English.[Doctoral dissertation, University of Cambridge] . -
Lowit, A. (2014). Quantification of rhythm problems in disordered speech: A re-evaluation.Philosophical Transactions of the Royal Society B: Biological Sciences, 369(1658). https://doi.org/10.1098/rstb.2013.0404 -
Mahr, T. J., Berisha, V., Kawabata, K., Liss, J., & Hustad, K. C. (2021). Performance of forced-alignment algorithms on children's speech.Journal of Speech, Language, and Hearing Research, 64(6S), 2213–2222. https://doi.org/10.1044/2020_JSLHR-20-00268 -
Malécot, A., Johnston, R., & Kizziar, P. A. (1972). Syllabic rate and utterance length in French.Phonetica, 26(4), 235–251. https://doi.org/10.1159/000259414 -
Maassen, B. A., & Terband, H. R. (2015). Process-oriented diagnosis of childhood and adult apraxia of speech (CAS and AOS).InM. A. Redford (Ed.), The handbook of speech production (pp. 331–350). Wiley. https://doi.org/10.1002/9781118584156.ch15 -
McLeod, S., & Crowe, K. (2018). Children's consonant acquisition in 27 languages: A cross-linguistic review.American Journal of Speech-Language Pathology, 27(4), 1546–1571. https://doi.org/10.1044/2018_AJSLP-17-0100 -
N. Miller, & A. Lowit (2014). Motor speech disorders: A cross-language perspective ( Vol. 12). Multilingual Matters. https://doi.org/10.21832/9781783092338 -
Mok, P. (2010). Language-specific realizations of syllable structure and vowel-to-vowel coarticulation.The Journal of the Acoustical Society of America, 128(3), 1346–1356. https://doi.org/10.1121/1.3466859 -
Mok, P., & Dellwo, V. (2008, May 6–9). Comparing native and non-native speech rhythm using acoustic rhythmic measures: Cantonese, Beijing Mandarin and English[Paper presentation] . Speech Prosody 2008, Campinas, Brazil. -
Murray, E., McCabe, P., & Ballard, K. J. (2015). A randomized controlled trial for children with childhood apraxia of speech comparing rapid syllable transition treatment and the Nuffield Dyspraxia Programme–Third Edition.Journal of Speech, Language, and Hearing Research, 58(3), 669–686. https://doi.org/10.1044/2015_JSLHR-S-13-0179 -
Ng, K. Y. M., To, C. K. S., & Mcleod, S. (2014). Validation of the Intelligibility in Context Scale as a screening tool for preschoolers in Hong Kong.Clinical Linguistics & Phonetics, 28(5), 316–328. https://doi.org/10.3109/02699206.2013.865789 -
Nip, I. S., & Green, J. R. (2013). Increases in cognitive and linguistic processing primarily account for increases in speaking rate with age.Child Development, 84(4), 1324–1337. https://doi.org/10.1111/cdev.12052 -
Nolan, F., & Asu, E. L. (2009). The Pairwise Variability Index and coexisting rhythms in language.Phonetica, 66(1–2), 64–77. https://doi.org/10.1159/000208931 -
Peterson, G. E., & Lehiste, I. (1960). Duration of syllable nuclei in English.The Journal of the Acoustical Society of America, 32(6), 693–703. https://doi.org/10.1121/1.1908183 -
Pike, K. L. (1945). The intonation of American English. University of Michigan Press. -
Pollock, K. E., & Hall, P. K. (1991). An analysis of the vowel misarticulations of five children with developmental apraxia of speech.Clinical Linguistics & Phonetics, 5(3), 207–224. https://doi.org/10.3109/02699209108986112 -
Prathanee, B. (1998). Oral diadochokinetic rate in adults.Journal of the Medical Association of Thailand, 81(10), 784–788. -
Prathanee, B., Thanaviratananich, S., & Pongjanyakul, A. (2003). Oral diadochokinetic rates for normal Thai children.International Journal of Language & Communication Disorders, 38(4), 417–428. https://doi.org/10.1080/1368282031000154042 -
Preston, J. L., & Edwards, M. L. (2009). Speed and accuracy of rapid speech output by adolescents with residual speech sound errors including rhotics.Clinical Linguistics & Phonetics, 23(4), 301–318. https://doi.org/10.1080/02699200802680833 - R Core Team. (2020).
R: A language and environment for statistical computing (Version 3.6.3) .R Foundation for Statistical Computing . https://www.r-project.org -
Robbins, J., & Klee, T. (1987). Clinical assessment of oropharyngeal motor development in young children.Journal of Speech and Hearing Disorders, 52(3), 271–277. https://doi.org/10.1044/jshd.5203.271 -
Rozenstoks, K., Novotny, M., Horakova, D., & Rusz, J. (2020). Automated assessment of oral diadochokinesis in multiple sclerosis using a neural network approach: Effect of different syllable repetition paradigms.IEEE Transactions on Neural Systems and Rehabilitation Engineering, 28(1), 32–41. https://doi.org/10.1109/TNSRE.2019.2943064 -
Rvachew, S., Hodge, M., & Ohberg, A. (2005). Obtaining and interpreting maximum performance tasks from children: A tutorial.Journal of Speech-Language Pathology and Audiology, 29(4), 146. -
Sehr, K. H. (2013). The study of diadochokinetic (DDK) rate and accuracy in typically developing children.Journal of the Korea Academia-Industrial Cooperation Society, 14(1), 321–327. https://doi.org/10.5762/KAIS.2013.14.1.321 -
Sharkey, S. G., & Folkins, J. W. (1985). Variability of lip and jaw movements in children and adults: Implications for the development of speech motor control.Journal of Speech and Hearing Research, 28(1), 8–15. https://doi.org/10.1044/jshr.2801.08 -
Skodda, S. (2011). Aspects of speech rate and regularity in Parkinson's disease.Journal of the Neurological Sciences, 310(1–2), 231–236. https://doi.org/10.1016/j.jns.2011.07.020 -
Sreelakshmi, R., & Murali, R. (2016). Comparison of speech measures between Tamil and Malayalam.Language in India, 16(8), 173–179. -
Stackhouse, J. (1992). Developmental verbal dyspraxia I: A review and critique.International Journal of Language & Communication Disorders, 27(1), 19–34. https://doi.org/10.3109/13682829209012027 -
Stackhouse, J., & Wells, B. (1993). Psycholinguistic assessment of developmental speech disorders.International Journal of Language & Communication Disorders, 28(4), 331–348. https://doi.org/10.3109/13682829309041469 -
Thoonen, G., Maassen, B., Gabreels, F., & Schreuder, R. (1999). Validity of maximum performance tasks to diagnose motor speech disorders in children.Clinical Linguistics & Phonetics, 13(1), 1–23. https://doi.org/10.1080/026992099299211 -
Tjaden, K., & Watling, E. (2003). Characteristics of diadochokinesis in multiple sclerosis and Parkinson's disease.Folia Phoniatrica et Logopaedica, 55(5), 241–259. https://doi.org/10.1159/000072155 -
To, C. K. S., Cheung, P. S., & McLeod, S. (2013). A population study of children's acquisition of Hong Kong Cantonese consonants, vowels, and tones.Journal of Speech, Language, and Hearing Research, 56(1), 103–122. https://doi.org/10.1044/1092-4388(2012/11-0080) -
Van Brenk, F., & Lowit, A. (2012). The relationship between acoustic indices of speech motor control variability and other measures of speech performance in dysarthria.Journal of Medical Speech-Language Pathology, 20(4), 24–29. -
vanHaaften, L., Diepeveen, S., Terband, H., De Swart, B., Van Den Engel-Hoek, L., & Maassen, B. (2021). Maximum repetition rate in a large cross-sectional sample of typically developing Dutch-speaking children.International Journal of Speech-Language Pathology, 23(5), 508–518. https://doi.org/10.1080/17549507.2020.1865458 -
Vuolo, J., & Goffman, L. (2018). Language skill mediates the relationship between language load and articulatory variability in children with language and speech sound disorders.Journal of Speech, Language, and Hearing Research, 61(12), 3010–3022. https://doi.org/10.1044/2018_JSLHR-L-18-0055 -
Wan, P., Huang, Z., Du, X., & Chen, Q. (2006). Clinical application of DR in improving the ability of oral-motor for hearing-impaired children.Chinese Scientific Journal of Hearing and Speech Rehabilitation, 21(3), 10. -
Wang, Y. T., Kent, R. D., Duffy, J. R., & Thomas, J. E. (2008). Analysis of diadochokinesis in ataxic dysarthria using the Motor Speech Profile Program™.Folia Phoniatrica et Logopaedica, 61(1), 1–11. https://doi.org/10.1159/000184539 -
Waters, D. M. (1992). An investigation of motor control for speech in phonologically delayed children, normally developing children and adults[Doctoral dissertation, Queen Margaret University] . -
White, L., & Mattys, S. L. (2007). Calibrating rhythm: First language and second language studies.Journal of Phonetics, 35(4), 501–522. https://doi.org/10.1016/j.wocn.2007.02.003 -
Williams, P., & Stackhouse, J. (1998). Diadochokinetic skills: Normal and atypical performance in children aged 3–5 years.International Journal of Language & Communication Disorders, 33, 481–486. https://doi.org/10.3109/13682829809179472 -
Williams, P., & Stackhouse, J. (2000). Rate, accuracy, and consistency: Diadochokinetic performance of young normally developing children.Clinical Linguistics & Phonetics, 14(4), 267–293. https://doi.org/10.1080/02699200050023985 -
Wong, A. W., Allegro, J., Tirado, Y., Chadha, N., & Campisi, P. (2011). Objective measurement of motor speech characteristics in the healthy pediatric population.International Journal of Pediatric Otorhinolaryngology, 75(12), 1604–1611. https://doi.org/10.1016/j.ijporl.2011.09.023 -
Yaruss, J. S., & Logan, K. J. (2002). Evaluating rate, accuracy, and fluency of young children's diadochokinetic productions: A preliminary investigation.Journal of Fluency Disorders, 27(1), 65–86. https://doi.org/10.1016/S0094-730X(02)00112-2 -
Yu, A. C. L., To, C. K. S., & Yao, Y. (2022). Child-directed speech as a potential source of phonetic precursor enhancement in sound change: Evidence from Cantonese.InA. C. L. Yu & D. Kavitskaya (Eds.), Life cycle of language: Past, present, and future. Oxford University Press. -
Yu, H, Jin, H .,Liao, Y ., &Li, Y . (2010, June 25–27). Analysis of reference normal values of diadochokinetic rate and US China comparison[Paper presentation] .International Conference on Computer Design and Applications (ICCDA), Qinhuangdao, China . -
Zheng, Y.-L., Bao, H.-Q. (2003).論普通話/N1C2/的協同發音 [On the co-articulation of N1C2 sequence in Mandarin] .第六屆全國現代語音學學術會議論文集 [Anthology of the Sixth National Modern Phonetics Symposium] , 37–43. -
Ziegler, W., & Wessel, K. (1996). Speech timing in ataxic disorders: Sentence production and rapid repetitive articulation.Neurology, 47(1), 208–214. https://doi.org/10.1212/WNL.47.1.208