Can the email notifications or admin interface be changed to another language?

1)  Emails / Invoices:  Unfortunately, no.  It's not possible to set the language of their communications.  However, what we tend to do (and find works well) is to include the first language at the top, with a note that the second language is below, then the second language below.

For example:

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(English Below)

Bonjour Bruce,

Merci d'avoir demandé de notre boutique. (Francais....)

-

Hi Bruce,
Thanks for ordering on our store.  (Rest of the English email goes here).

###

2) The Admin / backend is only in English.  That can't be changed either at this stage.  I've suggested this to Shopify, but so far it's only in English.

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Just for reference, actually neither of these are related to the theme.  The theme only manages the 'front end' of the website.  Email notifications and the admin interface both have to do with Shopify as a system itself.