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

Actually now that I think of it, sometimes we do omit the "u" in "su" and "tsu" when we're talking faster, since the ends of "ss" and "tss" already have a similar tone (?) to "u". When we include the "u" though, we don't pronounce it as its own letter as I mentioned above, we pronounce it combined with the "s" or "ts" as a single letter. To get the right sound for "su" and "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.)