Here are some languages he definitely spoke:
* Serbo-Croatian: His native language, which he used throughout his political career.
* Russian: He learned Russian during his time in the Soviet Union.
* German: He likely picked up German during his time in Austria, where he lived for a period.
* Italian: He spoke Italian due to his time in Italy and its influence in the region.
* English: While not confirmed as fluent, he likely had some knowledge of English, given his international interactions.
It's possible he had some knowledge of other languages as well, depending on his interactions with people from other countries. However, the languages listed above are the most certain.