For example the official language of the Croatian died and therefore Croatian administration prior to 1848 was Latin. Furthermore Latin was the only language that all the nations of the Empire would need to learn to the same extent and would be a unifying factor rather than a divisive one. Much of the trouble in the Austrian empire during 1848-49 revolutions had its origin in resentment and division that grew out of forceful implementation of "foreign" language into schools and administration while suppressing local languages.
Iirc a lot of Indians prefer English to Hindi for the same reason.