In the days of COVID-19 people are concerned with breath and speech micro-droplets and how far they travel without a mask.

This video I saw in Twitter, posits that Japanese people have it better because their language helps produce less exhaled air while speaking. Even though this particular argument is useless (since we can cherry-pick what ever phrases we want and make a language look good or bad), I was wondering if there is any truth to the general idea.

Are there significant differences in the air exhaled (both in volume and speed) between languages? Are there any studies done on this?

The speed is particularly important. For example, languages with bilabial stops (such as [p] and [b]) have moments when they suddenly release an amount of air that reaches much further than air from other sounds.

  • 2
    This review of the video clip (in Japanese) by Shigeto Kawahara, leading Japanese phonetician/phonologist, mentions Mielke 2011, in which "oral and nasal airflow were measured using a SCICON R&D Macquirer 516 transducer interface system and the associated oral and nasal masks."
    – Nardog
    Commented May 24, 2020 at 3:19

1 Answer 1


Are there significant differences in the air exhaled (both in volume and speed) between languages?

I would doubt it, and I would worry that it relates to individual anatomy more than the language itself. There are a lot of factors at play, and to my knowledge no studies of exit airspeed have been conducted. Linguists frequently study airflow which is volume per unit time, but speed is dependent on a lot of anatomically specific factors.

While many studies look at nasal airflow, these rates are usually for highly controlled environments rather than free speech, and the flow is usually only out of the nose rather than total flow out of the vocal tract. In running speech, the volume of air expelled may differ by context. For example, if you're speaking faster, each sound is articulated for less time so the amount of air exhaled per sound would likely also be reduced. Towards the end of phrases, your lungs are low on air, so if you're forcing it, you could probably get by with less air at the ends of utterances compared with the beginnings.

Determining the exit airspeed for a sound is also a hard question. Airspeed relates to the size of the opening, the pressure difference, and fluid viscosity (moist air has lower viscosity than dry air, for example). Air pushed through a narrow opening will be faster than air through a wider opening, all else being equal. However air pressure is modulated during speech, so air may not be pushed through at the same rate. Different sounds require certain pressure differentials which will affect exit air speed in a way that may overcome lip rounding. For example, the aerodynamic voicing constraint details the pressure difference required for voicing, but even in this case it is a pressure difference, not an absolute pressure, and the pressure a speaker generates with their lungs may be idiosyncratic. We may expect voiced sounds to have faster exit airspeeds than voiceless sounds on average, but any cross-linguistic generalizations will likely be dominated by anatomical differences.

  • Thank you for the interesting information (+1) I have not accepted the answer (yet). It offers some information and some speculation/opinion but does not fully answer the question.
    – Thanassis
    Commented May 29, 2020 at 10:56
  • My impression is that there are specific sounds that are the great "offenders", like the [p] I mentioned above. I also think that how much air different [p]s produce is not so much a function of individual anatomy but the language/culture. I might be wrong. I'd love to see data supporting the one or the other position.
    – Thanassis
    Commented May 29, 2020 at 11:00

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