From Ethnologue (http://www.ethnologue.com/language/jpn):
Population: 121,000,000 in Japan (1985). Population figure may include other ethnic groups. Population total all countries: 122,072,000.
Location: Widespread. Also in American Samoa, Argentina, Australia, Belize, Brazil, Canada, Hong Kong, Taiwan, Dominican Republic, Germany, Guam, Mexico, Micronesia, Mongolia, New Zealand, Northern Mariana Islands, Palau, Panama, Paraguay, Philippines, Singapore, Thailand, United Arab Emirates, United Kingdom, United States.
Dialects: Eastern Japanese, Western Japanese, Zu-zu-ben. Possibly related to Korean [kor]. Kagoshima dialect is 84% cognate with Tokyo dialect. Zu-zu-ben dialects unintelligible to other Japanese, and dying out as standard Tokyo Japanese takes over.
Typology: SOV; postpositions; demonstrative, numeral, adjective, possessive, relative clause, proper noun precedes noun head; adverb precedes verb; sentence final question particle; CV
Language Use: 1,000,000 L2 speakers.
Language Development: Taught in primary and secondary schools. Fully developed.
Writing: Braille script. Han, Hiragana, and Katakana scripts, primary usage.