The effect of healthy aging on within-speaker rhythmic variability: A case study on Noam Chomsky

Abstract

Speech rhythm varies noticeably from language to language, and within the same language as a function of numerous linguistic, prosodic and speaker-dependent factors, among which is the speaker’s age. Cross-sectional studies comparing the acoustic characteristics of young and old voices have documented that healthy aging affects speech rhythm variability. This kind of studies, however, presents one fundamental limitation: They group together people with different life experiences, healthy conditions and aging rate. This makes it very difficult to disentangle the effect of aging from that of other factors when interpreting the rhythmic differences between younger and older adults. In the present paper, we overcame such difficulty by tracing rhythmic variability within one single individual longitudinally. We examined 5 public talks held by Noam Chomsky, from when he was 40 to when he was 89. Within-speaker rhythmic variability was quantified through a variety of rate measures (segment/consonant and vowel rate) and rhythmic metrics (%V, %Vn, nPVI-V, n-PVI-C). The results showed that physiological aging affected speech rate measures, but not the durational characteristics of vocalic and consonantal intervals. More longitudinal data from numerous speakers of the same language are necessary to identify generalizable patterns in age-related rhythmic variability.

Age-related rhythmic variations : The role of syllable intensity variability

“…Evidence for decreasing speech rate with age is available from a single-subject longitudinal study based on public lectures of a well-known linguist and political activist, Noam Chomsky, over a timespan of about 60 years (Pellegrino 2019). Rhythmic changes as a function of age in terms of %V did not show in these data, which might be idiosyncratic and possibly attributed to this particular speaker being experienced in public speaking.…”

Age and gender effects in European Portuguese spontaneous speech

“…A commonly reported effect of aging on speech is that pause duration as well as the use of speech pauses tend to increase (Hartman & Danhauer, 1976;Steffens, 2011). The reduced speech (or articulation) rate with age has also been reported, regardless of the speaker's language Hazan et al, 2018;Hermes, Bourbon, & Cecile, 2020;Linville, 2001;Pellegrini et al, 2013;Pellegrino, 2019;Schötz, 2006;Smith, Wasowicz, & Preston, 1987;Volín, Tykalová, & Bořil, 2017). However, Jacewicz et al (2009Jacewicz et al ( , 2010, Brückl &Sendlmeier (2003), andGerstenberg et al (2018) did not find a decline in speech or articulation rate with aging.…”

“…The automated alignments of silent pauses were manually checked by two trained analyzers, who verified the accuracy of pause and speech intervals, and also labeled intervals with speaker or environmental noise. The intervals were labeled as: pause (breathing sound was considered as silent pause), speech, verbal non lexical (i.e., filled pauses), noise (i.e., noise that occurs during the speaker's pauses), vocal non lexical (i.e., laughter, coughing or other human noises), and speech with noise (i.e., speech intervals with environmental noise that could affect the acoustic measurements) (Pellegrino, 2019;Schuller et al, 2013).…”

“…Vocal non lexical phenomena were considered as pause time, while verbal non lexical phenomena were not included in the present analysis (Pellegrino, 2019;Tuomainen, Hazan, & Taschenberger, 2019). Speech intervals with noise were not counted for further analysis, and also the beginning and ending of all recordings were not pondered in the analysis due to sentence initial and final acoustic variability (a total of 7% of the speech intervals were excluded).…”

“…According to the World Health Organization, the number of people aged over 65 is rising, and by 2050, 1 in 6 people in the world will be over the age of 65, up from 1 in 11 in 2019 (United Nations Department of Economic and Social Affairs Population Division, 2019). Portugal is also one of the developed countries with the highest rate of older population (between 1970 and 2019, the percentage of people aged 65 and over increased from 9.7% to 22.4%) (Statistics Portugal, 2015, 2019United Nations Department of Economic and Social Affairs Population Division, 2019).…”