SafeAssign does more than translate words from one language to another. SafeAssign uses algorithms that make decisions about potential plagiarism based on word frequency, sentence structure, and other linguistic characteristics that are currently specific to the English language only.
Although SafeAssign officially supports only English, clients are welcome to attempt to use SafeAssign with languages other than English. SafeAssign has no technical limitations that preclude using it with other languages, but the results may vary and aren't guaranteed.
Blackboard is working to add official support for additional languages in SafeAssign in 2018.