Have you tried telling/asking them in some way? I would normally try to have a night out and buy some drinks and get the subject on discussion after hours. It

Have you tried telling/asking them in some way? I would normally try to have a night out and buy some drinks and get the subject on discussion after hours. It could be "as simple" as saying that they don't always have to speak English after hours or during lunch. Depending on what you think about that ofc.