Language Identifier Constants and Strings
Language identifier constants are deprecated and their use is discouraged. Use of locale names instead of locale identifiers is always preferable.
See language identifier for a description of language identifiers.
A primary or sublanguage identifier can be user-defined or predefined. For the predefined primary language identifiers with their valid sublanguage identifiers, see [MS-LCID]: Windows Language Code Identifier (LCID) Reference.
If there is no sublanguage identifier to use with a primary language identifier, your application should use SUBLANG_DEFAULT. It should use SUBLANG_NEUTRAL for resources that are the same for all sublanguages of a primary language.
A user-defined primary language identifier has a value in the range 0x0200 to 0x03ff. All other values are reserved for operating system use.
A user-defined sublanguage identifier has a value in the range 0x20 to 0x3f. All other values are reserved for operating system use.