When an UP.Phone generates a request, it indicates to the UP.Link server which language(s) it prefers to receive content in. The UP.Link server relays this information by setting the Accept-Language header in the HTTP requests it submits to HDML services. Normally, the Web server that hosts the HDML service converts this header to an environment variable named HTTP_ACCEPT_LANGUAGE. If you want your HDML service to provide localized content, you should check this environment variable and provide the localized content accordingly.
The Accept-Language HTTP header (and the HTTP_ACCEPT_LANGUAGE environment variable) specify a comma-separated list of language-country identifiers (as defined in ISO 639) and two-character country codes (as defined in ISO 3166). A list of these codes is provided at:
http://www.unicode.org
For example, the following is a typical identifier
This identifier indicates the UP.Phone prefers content to be in U.S. English.
The header lists language-country identifiers in order of preference. So, if the HTTP_ACCEPT_LANGUAGE environment variable specifies a list of identifiers, you should attempt to provide content according to the first possible identifier in the list.