Hello SlaVoip,
welcome to the Polycom Community.
You need to setup a local provisioning server in order to be able to load another language.
The community's VoIP FAQ contains this post here:
Oct 7, 2011 Question: How can I setup my Phone / Provisioning / Download / Upgrade / Update / Downgrade Software?
Resolution: Please check => here<=
Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.
Best Regards
Steffen Baier
Polycom Global Services