When conversing in less than ideal or “challenging” conditions, such as in background noise, talkers continuously monitor the success of the communication. In a case of communication break-down, they modify their speech in an attempt to make themselves more intelligible to the listener. These modifications include a range of acoustic-phonetic (e.g., slower, more intense and hyper-articulated speech) and linguistic adaptations (e.g., higher-frequency words, shorter and simpler sentences) often broadly referred to as “clear speech”. It has been shown that these speech modifications are modulated by complex interactions between various talker-related (e.g., age, regional accent), listener-related (e.g., age, hearing acuity, linguistic competence) and environment-related factors (e.g., room acoustics, background noise type; Mattys et al., 2012).
Our recent Economic and Social Research Council funded research project at University College London focused on few of these factors, namely how speech modifications and communication difficulty vary as a function of age and background noise type. In this project, we collected sensory, cognitive, speech production and perception data as well as self-evaluations of speaking and listening effort from 114 healthy Southern British English speaking participants aged between 8 to 80 years. For speech production, we recorded age- and sex-matched pairs while they carried out the “spot the difference” diapix task using the DiapixUK picture sets (Baker and Hazan, 2011) in conditions varying in the informational (three voices in the background) and energetic masking (speech-shaped noise) present. A secondary task (pressing a bell when hearing a dog barking but suppressing when hearing a car horn honking) was added to make the task more cognitively demanding, thus reflecting real-life multitasking situations. After completing each diapix task, both participants completed a paper-based questionnaire, answering questions about communicative difficulty and listening/speaking effort using an 11-point Likert scale. Baseline sensory and cognitive measures of hearing (pure tone audiogram), speech perception (coordinate response measure task, CCRM), cognitive function (tests of expressive vocabulary, letter-number sequencing, letter-digit substitution) and a standardised questionnaire of auditory disability (SSQ) were also collected.
In this talk, I will summarize the main results from the speech production and perception tasks (the diapix and CCRM tasks) and from the self-report measures (ratings of speaking and listening effort) that (some, not all!) show distinct developmental trajectories for different types of noise (speech vs. non-speech). Overall, our results suggest that when the background noise has a higher cognitive load, as in the case of other´s speech, children and older talkers need to exert more vocal effort to ensure successful communication. I will discuss these findings within the communication effort framework.
Alexis Dehais-Underdown (LPP)
Laurence Devillers (LISN, Sorbonne University)
Maria Giavazzi (DEC, ENS)
Didier Demolin (LPP)