New Site Checkout: Checkout is not translated to the language selected in the site creation flow

[Rolilink]

Quick summary

When a language different from english is selected during site creation, after finishing the flow and redirected to checkout the language goes back to english.

Steps to reproduce

1. Navigate into /new?ref=calypso-selector.
2. Select a different language.
3. Navigate through the flow steps until hitting the plan selection view.
4. Select any paid plan and click select.
5. Wait for site creation progress bar to be completed.

What you expected to happen

Checkout page should be translated to the language selected on the flow.

What actually happened

Checkout page goes back to english.

Context

No response

Browser

Google Chrome/Chromium, Mozilla Firefox, Microsoft Edge, Apple Safari, iOS Safari, Android Chrome

Simple/Atomic

Simple, Atomic

Other notes

No response

Reproducibility

Consistent

Severity

No response

Available workarounds?

No response

Workaround details

No response

[sirbrillig]

I noticed that the chosen language also does not persist into any other part of calypso. For example, when you reach your Customer Home page, it is also in English. Therefore this may be a general signup problem and not related to checkout.

[sirbrillig]

Two thoughts:

1. This may be gutenboarding-only and I'm not sure how often we use that flow.
2. This may actually work correctly if a new account is being created rather than a new site. This makes some sense since interface language is per-account rather than per-site, but it feels broken anyway.

[michaeldcain]

@simison: This seems to be an issue with Gutenboarding allowing the user to override their existing Calypso locale setting. Can you help triage this?