Get the RFC 3066 code for the language of the input data.
The Charset Detection service is intended primarily for detecting charsets, not language. For some, but not all, charsets, a language is identified as a byproduct of the detection process, and that is what is returned by this function.
CAUTION: 1. Language information is not available for input data encoded in all charsets. In particular, no language is identified for UTF-8 input data.
2. Closely related languages may sometimes be confused.
If more accurate language detection is required, a linguistic analysis package should be used.
The storage for the returned name string is owned by the UCharsetMatch, and will remain valid while the UCharsetMatch is valid.