Pay your workers a decent wage. Your company can definitely afford it. Don't be greedy.
Don't hire a manager that's going to discriminate against their employees simply because of their first language.
Treat management better
She's lazy and is always sitting in the break room on the phone.
Trust your hardworking employees that they know what they are doing. We know our customers, we see their reactions, we have actual conversations with them. Make yourself available for actual feedback. I was lucky to have a honest and hardworking manager who encouraged teamwork. But not all managers are willing to admit their way isnt working.