Respect course/user language hierarchy when sending certificates by email

[ibai-mutiloa]

Currently, when a certificate is generated and displayed inside Moodle, the multilang filter works as expected. The language shown respects Moodle’s usual hierarchy:

Forced certificate language (if defined in certificate settings)

Course forced language (if set)

User preferred language

Site default language

However, when the certificate is sent by email, this hierarchy is not respected. Instead, the email content always uses the site default language, regardless of the course language or user preference.

Steps to reproduce

Create a certificate using HelloHola.

Set a course forced language (e.g., Spanish).

Enrol a user with preferred language English.

Generate the certificate and send it by email.

[mdjnelson]

Thanks! I am currently preparing for a 2-3 week holiday but will see if I can get this in before then. :)