Due to the diversity in the workplace, the HR department should have developed standardized global HR policies that align with the organization's values. They must also provide a standardized global onboarding & training program that favors linguistic and cultural differences. In the end, regular audits of employees' performance will help to track the progression and room for improvement.
Your opinion is the same as mine. Standardized training is also an essential point for international organizations. In my opinion, ‘regular audits of employees' performance’ you mentioned could include feedback, so continuous evaluation is also important to ‘track the progression and room for improvement’.