The first thing I keep thinking is, if you haven't already, look into 5S and Lean. There is so much available for GMP and organization that you might be able to use, with the most important one for you being sustainability.
Although I cannot speak to the gloves in particular, for the language barrier use as many pictures as possible to convey the message you want. Make it standardized and so that its very obvious what you want. Post the pictures as needed throughout the facility (if you can laminate them so they can be cleaned). You can even include in training pictures of people doing things incorrectly and communicate what is not proper storage/GMP practices. After training, have them show you what to do so you know that they actually understand. Some of what you might be seeing is that the employees do not realize they aren't following procedure. (Also, the google translate app is a life saver for me. Many of our employees speak Spanish and so I have that on my phone and use it to communicate with them. I've noticed a big difference in their attitudes with me and effort to follow procedure.)
As furfarmandfork said, figure out why they are doing what they are doing, and come to a compromise as needed. If the storage location is the opposite direction of the lunch room, they might not want to take the time and energy to walk the opposite way for example. The more involved they are, the more likely you will have understanding and compliance.
Also, if they don't have any accountability they might not feel any of the consequences of not following GMP. If that means assigning gloves to each person... that might be the motivator for them to take care of the gloves. Be present in the production area and speak up as you see the NC occurring and communicate the proper procedure.
Going off of what Timwoodbag said, you can take that further and change the company culture around GMP. Give positive feedback for those following GMP. Assign team captains or shifts and award the shift/group that is always compliant (you'd have to have them fill out a checklist at the end or do it yourself to keep track of compliance). The award could be a free lunch or snacks in the lunchroom, even a gift card. This gives incentive to follow GMP. Everyone likes free things. Where I worked before we got to a strong place with our GMP and compliance so we implemented this to a lesser degree but still had it present. There were slips you could fill out throughout the building to recognize another person who went above and beyond for GMP, documentation, process improvements, Kaizen, 5S, safety etc. Each month a name was drawn and they would get a free lunch from the cafeteria. It really made a difference for how we viewed the rules and helping others. Each of the slips were given to the supervisors and then onto the person it was about after the draw so that they could read their coworkers appreciation of their actions. As I was mainly responsible for SOP updates there, I was constantly asking the operators for input and process improvements to align documentation with actual practices. I always submitted slips for helping me with documentation. The supervisors could see they were assisting with continuous improvement (a very big thing at that company usually included in their yearly evaluations), and the operators felt appreciated and were more likely to help me.
I also have always put in place as a part of my documentation system that people can come to me with "next revision requests" and leave them in a bin on my desk or message me directly. This system can be anonymous for those who are not comfortable coming forward and bringing up "issues" as long as the update they want is clear. This opens communication with the employees so you can understand their daily struggles and ways to improve it for them.
Sorry for the long post! I have a lot of experience with GMP & documentation which I thought might help you! Good luck with GMP and the first audit!!Go to the full post