Dynamic registration supports multi-lang in its own way in the dynamic registration requests. http://www.imsglobal.org/spec/lti-dr/v1p0

It does this by allowing a '#xx' suffix on some fields, where 'xx' is a language code. Currently, this is listed as supported on client_name (i.e. client_name#ja) and on message labels (i.e. label#ja). This issue deals with exploring whether we can produce the right country code data based on the Moodle language, such that we can properly support these translatable fields.