You can use the System.Globalization.CultureInfo class to get info about the language of the system.
CultureInfo.InstalledUICulture gives the culture of the OS
Some other CultureInfo you may find useful:
CultureInfo.CurrentCulture gives the culture info of the running thread, used when you need to know the culture, but aren’t displaying anything.
CultureInfo.CurrentUICulture gives the culture info for displaying things on the UI, such as the user desired format of DateTime.
Also take a look at this link
] for an example of using InstalledUICulture.