I answered a similar question a few months ago:

To what extent were Europeans who went on crusade multi-lingual? Both in terms of understanding other European languages and in terms of local languages? How did this change over time?

Short answer is most crusaders spoke French or a similar Romance language. But how did Icelandic, or Hungarian, or Swedish, or Russian crusaders communicate? It's not clear, but they probably used Latin or Greek. The Middle East was an extremely multilingual place so there were already professional interpreters and translators, who were easily adapted into crusader administration.