[1] OAuth 1.0 API Reference - Google Accounts Authentication and Authorization — Google Developers (2014-12-05 11:52:26 +09:00 版) https://developers.google.com/accounts/docs/OAuth_ref#GetAuth

hl (optional) An ISO 639 country code identifying what language the approval page should be translated in (for example, 'hl=en' for English). The default is the user's selected language. This is a Google-specific parameter.