There are several theories as to the origin of "desu"; one is that it is a shortened form of であります "de arimasu", which is a polite form of である "de aru". In general, both forms are used in only writing and more formal situations. Another form, でございます "de gozaimasu", which is the more formal version of "de arimasu", in the etymological sense a conjugation of でござる "de gozaru" and an honorific suffix -ます "-masu", is also used in some situations and is very polite. Note that "de aru" and "de gozaru" are considered to be compounds of a particle で "de", and existential verbs "aru" and "gozaru". です "desu" may be pronounced っす "ssu" in colloquial speech. The copula is subject to dialectal variation throughout Japan, resulting in forms like や "ya" in Kansai and じゃ "ja" in Hiroshima (see map above).