caotope <[log in to unmask]> writes:
> The *falling* diphthongs /ie y2 uo/ derive from historical /e: 2: o:/.

Falling?  I pronounce 'Tuomas' something like [twOmas], i.e., the 'o'
is more prominent, so this should be a rising diphthong.

> AFAIK *rising* difthongs do stem mostly from vowel + glide.
> ...

Again, you mean the reverse, no?  From glide + vowel?  Otherwise I'd
expect the first element to be more prominent.