I am going to give some more advice here, and you may not be happy about it. So be forewarned.  The upshot of the previous Light Bulb Moments is that bilingual supervisors need more support than they are getting in ensuring that employees really understand and value their benefits packages.  We strongly recommend that they get some training, designed for them and their unique situation, particularly around this issue.

Before conducting your enrollment meetings for all employees, carve out some time to address bilingual supervisors alone.  “What?” you will object.  Perhaps you barely have time to schedule regular OE meetings, and you are already getting pushback from the folks in production on that.  Perhaps there is way too much on supervisors' plates as it is, and you feel you can't ask them to take on anything else.  After all, benefits communication is not part of supervisors' job description, so why should you spend time, much less, money on it?