What

This is a proposal to add a translation navigation/language toggle component or pattern to the Design System.
This proposal is somewhat related to (but more specific than) #99

The purpose of this component would be to allow users to switch between the English language version of a page and any other language(s) the page may be available in, Welsh being the most common use case.

With two languages (most common):

With multiple languages:

Why

There are slightly different implementations of this component across government.

• GOV.UK have a "Translation nav" component in the govuk_publishing_components library. This is used very broadly across publications on GOV.UK
• HMRC Frontend has a similar "Welsh Language Toggle" component
• There is a very similar "Help users to Toggle to Welsh" pattern in the DWP Design System
• The One Login home team in DI have just added a similar component to their frontend application, roughly modelling it after the GOV.UK version

There might be other similar components since many services are available in Welsh and there is a real need to easily switch between languages.

There are many challenges/consideration around this component, such as best practices on accessibility and semantics.

It would be great if this could be standardised.