Speech Timing in Typically Developing M andarin-Speaking Children From Ages 3 To 4 (2022)

Abstract: This study aims to develop a better understanding of the speech timing development in Mandarin-speaking children from 3 to 4 years of age. Data were selected from two typically developing children. Four 50-min recordings were collected during 3 and 4 years old based on natural conversation among the observers, participants, and the parents, and the picture-naming task. Speech timing were measured by Praat, including speaking rate, articulation rate, mean length of utterance (MLUs), mean utterance duration, mean word duration, pause ratio, and volubility. Major findings of the current study are: 1) Five measurements (speaking rate, mean length of utterance(MLUs), mean utterance length, mean word duration and volubility) decreased with age in both children; 2) Articulation rate of both children increased with age; 3) Comparing with the findings from previous studies, pause ratio of both slightly increased with age. These findings not only contribute to a more comprehensive data for assessment, it also can be a reference in speech intervention.

## introduction speech timing, also known as speaking rates, is a product of several factors, including biological factors (e.g., anatomic growth, neurologic and neuromuscular maturation), sensorimotor and language processes (e.g., motor learning, and semantic, lexical, and phonologic access, and motor programming and planning) @xcite @xcite . speaking rates could be a crucial indicator of typical speech development and speech disorders, for example, stuttering, cluttering, specific language impairment, apraxias, and dysarthrias. @xcite @xcite . speaking rate not only serves as a metric, it can also be a common target in speech intervention to improve speech production in individuals with speech motor involvement. ## findings major findings of the current study are: 1) except for the articulation rate and pause ratio, other five measurements (speaking rate, mean length of utterance (mlu), mean utterance length, mean word duration and volubility) decreased with age in both children; 2) articulation rate of both children increased with age; 3) comparing with the findings from previous studies, pause ratio of both slightly increased with age. the measures of each recording from the two participants were presented in figure 1 and figure 2 describe the distribution of speech rate of two participants in 3 and 4 years old. in both participants, the speaking rate, mean length of utterance (mlu), mean utterance length, mean word duration and volubility decreased with age, while the articulation rate and pause ratio increased with age in both children. in 4 years old, the articulation rate and pause ratio of child a are less than those in child b (figures 3 and 4 ). 6 discussions 6.1 comparision of speech rates with previous studies in general expectation, speaking rate will increase gradually with age (nip and green, 2013; tingley and allen, 1975), while the pausing ratio will decrease with age. results of this study show, contrary to expectations, that a developmental increase in speaking rate did not occur. the findings of the present study, together with those of pindzola et al. (1989), hall et al. (1999), amir and grinfeld (2011) and walker and archibald (2006) suggest that speaking rate may not increase with age in the preschool years. however, it is possible that speech rate development are nonlinear. in amir and grinfeld (2011), for example, the articulation rates of hebrewspeaking participants (@xmath0;0=137.70 word per minute (wpm); 5;0=132.95 wpm; however increased at age 7 and 9 (7;0=162.13 wpm; 9;0=174.64 wpm). the increasing of pausing ratio suggest that children attempt to use more complex linguistic structures, especially by around age 3 @xcite . moreover, the correlation between speech rate and pause ratio is observed from the data, which is as the pause ratio increases, the speech rate decreases. only a few studies have reported sex differences in speech rate @xcite . in this study, the girl (child a) speaks faster than the boy (child b), but further statistical analysis is needed to prove if there are any significantly differences. in contrast, the boy produced significantly shorter utterances at age 3;0 (girl's @xmath1.520; boy's @xmath2.058) and 4;0 (girl's @xmath3.978; boy's @xmath4.983). comparing with previous studies, these findings are controversial because most studies that reported sex comparisons did not find differences (e.g., @xcite or showed the opposite pattern in which preschool girls spoke slower than preschool boys @xcite .