User blog comment:JapaneseOPfan/Lesson 12 or something (Pronunciation)/@comment-1595565-20150813214305/@comment-3345720-20150813225836

Actually now that I think of it, sometimes usually we do omit the "u" in "su" and "tsu", since the ends of "ss" and "tss" already have a similar tone (?) to "u" anyway, and it's just a waste of breath to actually make the u sound.

When we do include the "u" though, we don't pronounce it as its own letter as I explained in the comment above, we pronounce it shorter, combined with the s or ts, as a single letter. To get the right sound for す(su) and つ(tsu), try saying those letters without moving your lips at all.

And each syllable still usually gets the same length and emphasis. (sa. ss. ke., ah. ss. ka., ee. ts. ki.)