[subroutine]

You're saying phonology is the new phrenology?

Jokes aside, I agree that estimating the average absolute information content of a syllable seems pretty absurd.

However, if the primary goal here was to determine whether some languages convey more information per unit time than other languages, I think the authors did fine. To this end, they needn't define information per syllable in anything other than p.d.u. - procedurally defined units. If average Vietnamese speech has 2x the number of syllables/min as German, but it takes the same amount of time to recite War and Peace in both Vietnamese and German, it suggests that both languages convey the same high-level information 'per unit time', but not 'per syllable'.

And basically that's all they did... "We computed the ratio between the number of syllables [in the text passage] and the duration [it took to recite the passage]"