Page 50 - Basic Japanese
P. 50
Notice that the vowel u gets unvoiced or dropped when
there is a following voiceless consonant:
[cue 01-16]
s ts
suki [s-ki] likable tsuki [ts-ki] moon
susumu [s-su-mu] tsutsumu [ts-tsu-
advances mu] wraps up
susuki [s-su-ki] tsutsuki [ts-tsu-
pampas grass ki] pecking, biting
After you have practiced on the difference between tsu
and su for a while, you might try these tongue-twisters:

