The American Stroke Association uses the 'BE FAST' acronym as a mnemonic device to identify the six warning signs of a stroke. Each letter represents a physical indicator that requires immediate attention: B (Balance loss/dizziness), E (Eye changes like blurred or double vision), F (Face drooping or uneven smile), A (Arm weakness or numbness), S (Speech difficulty/slurring), and T (Time to call 911).