How to get the SMF forum in different language?
To install SMF and choose your preferred language, go to your Site Tools > Site > App Manager.
From the Application drop-down menu, select the application you want to use. Fill in the Application Setup and Admin Info details. Click Install.
Login to the admin area of your website and go to Admin > Configuration > Languages > Add Languages. Click on Search and all language packs will be listed. Use Install for the preferred one to be set on your website.