The English language is unusual in that it does not have a grammatical way to indicate hierarchy. For new international students from cultures with strict linguistic and behavioral codes to show respect, it is a challenge to navigate the standard American system. To further confuse the situation, the faculty within a particular university varies in their levels of familiarity. Some conduct themselves, their classes, and their interactions with a formality that may be comfortingly familiar to some international students. Informality, however, seems to be more common.
Instructors regularly sit on desks, swinging their legs as they talk or listen.
There is, in fact, much more negotiation of hierarchy in American academic life than international students are likely to have encountered. It is confusing. The result may be inappropriately passive or inappropriately, bold demeanor in the classroom. Many problems can be avoided if instructors are aware of potential difficulty, if they explicitly acknowledge their own styles and motivations, and if they clearly state their expectations in matters such as classroom behavior and terms of address. The cultural diversity in American universities is an exciting resource.