JIRA Issue Collector language settable by javascript

Following the page:
https://confluence.atlassian.com/display/JIRA/Advanced+Use+of+the+JIRA+Issue+Collector
it describes very well how the language is selected.
However, for use cases where the end user does not have a JIRA account and I want to display the issue collector in another language, it is not possible.

It would be awesome to have the same mechanism working as for the email or fullname fields, eg.

fieldValues :

{ fullname : 'Name', email : 'email@dot.com', language: 'PL' }