Japanese is spoken primarily in Japan.
All vowels may appear long, as may all
obstruents - long vowels accent placement may be on
either element. Shibatani (1990) reports final nasals as
uvulars, varying with the nasalized counterpart of the
preceding vowel. /t, d, s, z/ are replaced by
palato-alveolar affricates or fricatives before /i, e/.
/t, d/ are [ts, dz] before /u/. Some analyses regard
these sibilant variants as phonemic because of a residue
of problematic cases. Bloch (1950) and Horne (1963) both
report that /t, d, n, s/ are dental before /a/; this
variant is taken as underlying.

Bloch, B. 1950. Studies in colloquial Japanese, IV:
Phonemics. Language 26: 86-125.

Jorden, E.H. 1963. Beginning Japanese, Part I. Yale
University Press, New Haven.

Martin, S.E. 1952. Morphophonemics of Standard Colloquial
Japanese (Language Dissertation 47). Linguistic Society of
America, Baltimore.

Shibatani, M. 1990. The languages of Japan. Cambridge
University Press, Cambridge.