IANAMD but simply using various accents, by itself, is perhaps less relevant clinically than the emotional disregulation and socially maladaptive behavior you describe.

Unchecked, compulsive aggression with fixation that requires coworkers to physically extract themselves (harassment) is certainly diagnosable, but not by us or by you.

This should be addressed formally by a superior, if only so that your coworker has the documentation necessary to get the help they need. Your coworker will not remain so for long if this continues.