It depends on the job you are applying for. Knowledge at the basic communication level is most often desirable if the job you are applying for does not require a higher level of knowledge of a specific foreign language. Sometimes knowledge of the language is not necessary at all.
Accommodation is organized, but not free. Most often it is organized in double rooms, but sometimes there is an option of single rooms. The candidate pays it. The daily commute to work is free, and transportation from Croatia to the city where the job you are applying for is sometimes organized, and sometimes the candidate comes at his own expense.