Most acoustic studies of sibilant fricatives focus on languages that have a place distinction like the English distinction between coronal alveolar /s/ and coronal post-alveolar /ʃ/. Much less attention has been paid to languages such as Japanese, where the contrast involves tongue posture as much as position. That is, the Japanese sibilant that contrasts with /s/ is /ɕ/, an alveolopalatal fricative that has a “palatalized” tongue shape (a bunched predorsum). This paper describes measures that can be calculated from the fricative interval alone, which we applied both to the place distinction of English and the “palatalization” or posture distinction of Japanese. The measures were further tested on Mandarin Chinese, a language that has a three-way contrast in sibilant fricatives contrasting in both tongue position and posture.