What percentage of vital capacity (VC) is typically inhaled during speech?

In speech production, individuals typically inhale a substantial portion of their vital capacity (VC) to ensure adequate airflow and pressure for speech generation. The average percentage of vital capacity that is usually used during speech is around 60%. This percentage allows for the necessary lung volume to support extended utterances and maintain a steady air pressure, which is essential for producing clear and sustained speech sounds.

Inhalation during speech is generally more significant than during restful breathing. The ability to inhale this volume ensures that the speaker has enough air support for phonation and articulation, resulting in better speech clarity and volume. While the percentages for inhalation may vary slightly based on the specific context of speech or individual factors, 60% is recognized as a typical value in speech science literature, reflecting the physiological demands of producing speech over longer phrases or sentences.