Problem: If I send an invoice to a client via the Invoice app, the email they receive is in English -- even when my personal language choice is French and the resulting invoice is available for download in French in my account.

Easy fix: please send the email and the invoice link in the navigation language chosen by the user, or:

Ideal fix: add a "language" field to the "client" record and send the email and the invoice link in that language. This way, there is no need to toggle your account setup when you send an email to another language speaker.