Supporting language attribute tags other than en and fr

Description

As a current user at IRCC (consulate abroad) or future Notify user of a language other than English and French, I need to be able to add the correct language attribute tag so that screenreaders can read texts in the correct language.

WHY are we building?

Feature doesn't exist yet but IRCC is already sending out messages in 10 languages other than English and French and those may not be readable by screenreaders.
Storytelling is writing a blog on the multilingual service this quarter and it would be great to state that we're working on it by publishing time

WHAT are we building?

New language attribute tags

VALUE created by our solution

Improve existing service's accessibility
Open up more languages for future services
Priority should be for Inuktitut and Inuinnaqtun as well since there is a Service Canada pilot in the works

Documentation and Artifacts

Good docs, figma mockups, ADRs, screenshots etc.

Acceptance Criteria

Given some context, when (X) action occurs, then (Y) outcome is achieved

[ ] Cypress UI tests if needed.
[ ] Generate appropriate log messages so that executions of this feature can be tracked
[ ] Can misuse of this feature cause harm? If yes, create an alert
[ ] Update the status of related findings, insights, and hypotheses on the Research Airtable
[ ] Once change/fix/feature is implemented, link relevant Airtable records to design artifacts (Figma)
A11y
Bilingualism
Privacy considerations
Security controls in place
Measuring success and metrics

Related Research Airtable records

(Ping Adrianne to add stuff here or find stuff yourself)

QA Steps

[ ] Tested in a realistic production scenario

GC Articles Publish checklist

[ ] Supporting feature is released and unflagged
[ ] Create or update slug
[ ] Page content and slug is translated
[ ] Document links to and from the page
[ ] Add page slug and title to inventory
[ ] If new page, add WAF rule
[ ] Create new page or update existing page content
[ ] Create or update translation to the page
[ ] Link translations by choosing an assigned translation
[ ] If new page, save as draft
[ ] If existing page, update the page
[ ] Post page in Slack for last minute reviews
[ ] On staging: Clear the cache through GC Notify's admin panel
[ ] On staging: Check links, images and language toggle
[ ] Give a heads up to the app-team channel once ready to publish
[ ] On staging and production: Clear the cache through GC Notify's admin panel
[ ] Clear Cloudfront cache in GCA as needed (Andrew and Phil are GCA admins)

cds-snc / notification-planning