Our customers are located in Russian and CIS. So, the most common language is Russian. Telerik WinForms controls doesn't provide official Russian localization. Yeah, we can translate it, but it's too hard to contact with translators and support them in translation questions. And, of course, it takes money resources. We'd rather pay more monay for Telerik WinForms UI with official Russian localization than we spend money to translators. Thanks!