You have to go to the user profile.
In user preferences, select the language:
If the language you are looking for is not in the list, please contact us so we can consider including it. https://partners.athento.com/doctypes/public/create/e58a5dcf-64c4-48d3-8aee-09f1c173490b/6765a44c-f683-4cf4-996f-c922caf249cb
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