Evaluating rate and accuracy of real word vs. non-word diadochokinetic productions from childhood to early adulthood in Hebrew speakers

Background: Oral-Diadochokinesis (oral-DDK) tasks measure how quickly and accurately one can repeat a series of target sounds. Thus, they are a popular tool for evaluating oral-motor skills for individuals with various speech disorders. Typically, oral-DDK tasks involve rapid repetition of non-words. For several populations (e.g., young children, older adults), it has been suggested that repetitions of real words may be more suitable, commonly resulting in faster rates. Yet, the literature is either silent or inconsistent regarding this real-word repetition advantage for other age groups, from preschoolers to young adults. It is not clear whether performance accuracy is affected as well. Specifically, for Hebrew speakers, this data is missing. Aims: The goal of this study was to compare rate and accuracy for non-word and real-word repetition, in four groups of Hebrew-speaking individuals; preschoolers (5 years old), younger elementary school children (7 years old), adolescents (15 years old) and young adults (25 years old). Secondary goals were to provide a developmental pattern for oral-DDK rates for Hebrew speakers, and to compare it to the English norms. Methods & Procedures: All participants (n=150) had typical speech and language development. They were asked to repeat “pataka” (non-word) and “bodeket” (Hebrew real word) as quickly and accurately as possible for 10 sec. Production rates (syllables per second) and accuracy (on a 5-point scale) were measured. Outcomes & Results: As expected, oral-DDK rates gradually increased with age, with similar rates for both real- and non-words. Accuracy scores were higher for real- than non-word repetition, across all age groups. For the group of school-age children, the Hebrew rates differed from the English ones. Conclusions & Implications: A real-word repetition advantage was documented only for repetition accuracy, but not for rate. These findings can be explained as each stimulus involves different demands on an individual's neuro-motor and linguistic processing abilities. Further research using real- and non-word tasks should be conducted with clinical populations to assess whether both procedures could assist in differential diagnosis between various speech disorders. Finally, the large differences between children of different ages, as well as the apparent rate differences between Hebrew and English, highlight the need to create age- and language-sensitive norms.