Objectives:
A persistent challenge in voice therapy is skill transfer—patients often demonstrate improved voice use in the clinic but struggle to apply these techniques in daily communication. One major barrier to transfer is the presence of environmental noise, which places additional cognitive demands on the speaker and may interfere with the intentional use of therapeutic speaking styles. Clear speech, an intelligibility-enhancing technique used in voice therapy, requires increased articulatory precision, slower rate, and greater pausing, intentional speech modification that can elevate cognitive load. However, it is unclear how different types of background noise influence speakers’ ability to maintain clear speech and how such conditions affect perceived mental effort during spontaneous communication.
Method:
Ten vocally healthy adults (ages 19–25) produced spontaneous speech under six conditions: two speaking styles (clear, habitual) crossed with three noise types (quiet, informational masking, energetic masking). Informational masking consisted of two-talker babble containing linguistic content, while energetic masking was created by time-reversing the same babble to preserve acoustic energy while eliminating intelligible speech. Participants described DIAPIX images for 90 seconds per condition while being recorded in a sound-attenuated booth. Following each trial, they rated perceived mental effort. Speech rate, number of pauses, and total word count were analyzed to evaluate the participants ability to maintain clear speech during the trials.
Results:
Talkers successfully differentiated clear and habitual speech in quiet and informational-masking conditions but not in the energetic masking condition. Despite similar acoustic energy levels, clear speech modifications were not sustained in energetic masking noise, suggesting that the perceptual strangeness of reversed speech may have distracted talkers or disrupted attention allocation. Word count decreased during clear speech in quiet and energetic masking but not in informational masking. Perceived mental effort did not differ across conditions, indicating limited self-awareness of cognitive demand.
Conclusion:
The inability to maintain speech modifications in energetic masking noise highlights how atypical or distracting environments can interfere with the intentional control of therapeutic speech techniques. Incorporating various noise contexts into therapy may therefore facilitate better generalization and automaticity of clear speech in daily communication.