Final answer:
In American legal English, 'shall' is used in a binding and unconditional manner, while 'may' expresses permissiveness or possibility.
Step-by-step explanation:
In American legal English, the word 'shall' is used in a binding and unconditional manner, indicating an imperative action. It replaces 'must' or 'have to'. For example, 'The plaintiff shall...' means that the plaintiff is required to take a certain action. On the other hand, the word 'may' is used to express permissiveness or possibility. It is not mandatory and indicates a choice or option.
The terms "shall" and "may" are commonly used in legal and contractual language, and they convey different degrees of obligation or permission.