entityform email multilingual
This is not answer to your question - but a tip on the way...

There is a good possibility to use Rules + some rules contrib module to do this, maybe in a better way because rules is also able to send node-fields-values trough Tokens id, and also capable to act on site-current-user:language from the users own default language and send mail in preferred user language. Rules can be triggered on different actions at the site.
One of my Rules setting sending mail, where all fields-name are translated together with the fields value, based on user-default-language settings.