I've never heard about "Bosnian" language. As I know people in Bosnia speak Serbo-Croatian. Serbs use cyrillic alphabet, Croats use Roman letters.
from: http://en.wikipedia.org/wiki/Bosnian_language

The Bosnian language (bosanski jezik or босански језик) is one of the standard versions of the Central-South Slavic diasystem, based on the Štokavian dialect. The language is spoken by Bosniaks in Bosnia and Herzegovina, the region of Sandžak (in Serbia and Montenegro) and elsewhere. It is based on the Western variant of the Štokavian dialect. The Bosnian alphabet is based on Latin. Cyrillic alphabet is accepted (chiefly to accommodate for its usage in Bosnia in the past, during the time of former Yugoslavia), but seldom used in today's practice. The name Bosnian language is the commonly accepted name among Bosniak linguists, and the name used by the ISO-639 standard.