[Cookingboy]

By monosyllabic he meant one short syllable only, or "mora":

https://en.wikipedia.org/wiki/Mora_(linguistics)

Eight, for example is one syllable with two moras, the "eigh" sound and the "t" sound at the end.

Same for Zero, which as "Ze" and "Ro" separated into two moras.

Nine, Five, Four, Three, Two, One, for example are one mora words.

Six actually has 3 mora, with "Si" at the beginning and the X at the end having two mora "k" and "s" sound.

In comparison all Chinese characters have one mora only, thus it's much faster and easier to use in numbers.

[moate]

A valid point, but that's not what he literally said. We're all being pedantic here (nothing wrong with that, we're discussing linguistics after all).

I was just pointing out that he's literally wrong, and if that's what he meant he should be more clear in his phrasing.