Normally a big company won't fire an employee w/o

following a docummented process:
1) Warning. Clearly point out the performance of the employess is below expectation.
2) Three-month or 6-month probation. Set a clear career plan for the employ to improve a few aspects at work. Each item should have quantifiable criteria for meeting or missing the goal.
3) At the end of the probation period, convene a meeting and evaluate the overall performance. Then make a decision on the fate of the employee.

HR and supervisor will be involved. HR has to document such process.

In your hubby's case, talk to the HR and ask for explanation about what the supervisor has said. Ask for the standard protocol of firing employee. Insist to have all written documents of the company's policy regarding this issue. Document his discussions with HR and supervior.

Lastly, your hubby needs to improve his communication skills and stops speaking Chinese at work when possible.

One muggle