In EXM under delivery tab there is a Personalization checkbox. Can it be set to checked by default? This is on a 9.0.2 installation.
Please double check that you really want to do this since this is meant for a specific purpose. However, you can do this:
- Go to /sitecore/templates/Email Campaign/Messages/Mail Message/__Standard Values
- Check the "This email uses personalisation" Checkbox.
Since, this is a shared field so no matter what language you use for the Email campaign, it will always be checked.
I hope this helps.