The installation of OEDK: Classroom Edition is made silent and uses default options, including a default language of English. If you wish to set the language to another locale then you need to follow these instructions. The standard install includes some of the common languages and others are included in the supplemental progress messages file - which you can download here.
As an example, here are the steps you need to follow to setup Russian PROMSGS or you can read the PROMSGS installation doc.
You can repeat this process for other languages available in the PROMSGS or SUPPROMSGS files.