2.1.1405 Part 4 Section 18.104.22.168, ST_TextLanguageID (Language ID)
a. The standard states that the ST_TextLanguageID specifies an ID representing a particular language.
In Office, the language ID consists of an ISO 639-1 letter code followed by a dash and then an ISO 3166-1 alpha-2 letter code. The contents of this language shall be interpreted based on the context of the parent element.