The Wage and Hour Division of the Department of Labor enforces labor laws regardless of immigration status.
No employer should have an unfair advantage because he or she employs undocumented employees and doesn't pay them. Look at the Fact Sheet on Undocumented Workers which is available in English, Chinese, Korean, Spanish, Thai, and Vietnamese. It says the WHD will enforce pay for hours worked for covered, non-exempt employees regardless of whether they are documented or undocumented.
Wage and Hour staff members are fluent in many languages. The Department of Labor has an interpretation service which can assist with translation in more than 170 languages.
The Wage and Hour Division administers many programs for nonimmigrant workers and certain qualifications apply.