GCompris is internationalized and is available in more than 35 languages. If you want to check if your language is available, you can start GCompris and select your language in the option of configuration.
Be careful, some languages need specific fonts to be displayed correctly.
If your language is not supported, you can contribute to the software and add the translation of your language. If you are interested, you can contact the translation team of the KDE project for your language. You can check the level of translation for your language on the KDE translation web site.