I understood the message would be displayed in my email only in the
language of my browser.
I'm not sure where you got that from. Your e-mail program is not
supposed to know about (or care about) your browser's settings. Besides,
there is no way to send out an e-mail in such a way that the recipient
will only see a part of it (that is in a given language, for example).
My suggestion would simply be to host all the content on the web, and
have all the links to all the languages in a plain-text e-mail.