As far as I can find Catan has been released in the following 39 language versions.

Afrikaans, Arabic, Basque, Brazilian, Bulgarian, Catalan, Chinese, Croatian, Czech, Danish, Dutch, English, Estonian, Finnish, French, German, Greek, Hebrew, Hungarian, Icelandic, Italian, Japanese, Korean, Latvian, Lithuanian, Macedonian, Norwegian, Polish, Portuguese, Romanian, Russian, Serbian, Slovak, Slovenian, Spanish, Swedish, Taiwanese, Thai, and Turkish.

The Brazilian versions use the local spellings of Portuguese so I list them as a seperate dialect/edition. Equally I have Chinese language sets manufactured for the Taiwanese market so list these seperately too. I  also have a Turkish version of Catan produced by Kosmos that I have been unable to find details on, but list it too.

Currently I have 37 and am missing the Afrikaans version and Macedonian languages from my collection.