PLATUI-2910: Added lightweight ADR regarding decision to not use Mess…

…ages for hardcoded strings from hmrc-frontend inTwirl templates at this time (#299)

docs/maintainers/adr/0022-can-we-replace-language-params-in-components-with-play-messages-api.md

@@ -0,0 +1,35 @@
+# Can we replace the string `language` params in `hmrc-frontend` components with Play Messages API?
+
+* Status: rejected
+* Date: 2024-04-22
+
+## Context and Problem Statement
+
+At the moment, components in `play-frontend-hmrc` based on components from `hmrc-frontend` can take in a `language` parameter 
+if the template contains text strings. These are modelled in the hmrc-frontend library as strings of “en” or “cy”. 
+Currently we have a Scala case class that models this, which is a trait Language that can be either `En` or `Cy`.
+
+However, Play framework supports multilingual strings via the Messages API, whereby messages are stored in `messages` 
+and `messages.cy` and translated based on the value in the `PLAY_LANG` cookie. A spike was played to see whether it was
+possible to replace current implementation of passing a string on "en" or "cy" to a template by using the Messages API.
+
+## Decision Drivers
+
+* This was documented in the spike write-up document in PLATUI-2910. Please see the document linked from that ticket for
+  a full write-up.
+
+## Considered Options
+
+* Replace use of `lanaguage` string with use of Play Messages API.
+
+## Decision Outcome
+
+Chosen option: Do nothing at this time. 
+
+This is because this would like be impactful on service teams (although the size of the impact was unknown) with little 
+benefit for services unless they want to support more langauges than English and Welsh. Given that making any chane 
+would definitely be an impactful breaking changes requiring re-writing of service code by teams, the decision was made
+not to undertake the work at this time now that the changes needed are better understood from the spike.
+
+For a fuller write-up of all this, please read the spike write-up document linked in PLATUI-2910.
+

docs/maintainers/adr/index.md

@@ -23,6 +23,7 @@
 * [ADR-0019](0019-add-welsh-language-support-to-govuk-accessible-autocomplete.md) - Add Welsh language support to the GOVUK accessible autocomplete wrapper
 * [ADR-0020](0020-reduce-support-for-internet-explorer.md) - Reduce support for Internet Explorer
 * [ADR-0021](0021-defer-inclusion-of-password-field.md) - Defer Inclusion of Password Field from govuk-frontend v5.3.0
+* [ADR-0022](0022-can-we-replace-language-params-in-components-with-play-messages-api.md) - Can we replace the string `language` params in `hmrc-frontend` components with Play Messages API?
 
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