Slovenian is a Southern Slavic language spoken by about 2 million people in Slovenia and also in Argentina, Australia, Austria, Canada, Croatia, Hungary, Italy, USA. Other Southern Slavic languages include Serbian, Croatian, Macedonian and Bulgarian.
Slovenian is closely related to Croatian and Serbian, particularly to the Kajkavian and Čakavian dialects, and is in fact more or less mutually intelligible with Kajkavian Croatian dialects.
source
wikipedia.org,
omniglot.com,
evertype.com &
ethnologue.com