Pilots communicate with air traffic control (ATC) using radio communication. ATC issues instructions and information to pilots, such as clearance for takeoff or landing, altitude changes, and weather updates. Pilots respond with their aircraft identification and the appropriate phraseology, such as "Roger" or "Affirmative," to acknowledge and comply with instructions. Pilots may also communicate with ATC to request assistance or report emergencies. ATC and pilots use standard phraseology and protocols to ensure clear and concise communication.