Chapter 4 - Section 2.
Radio Communications Phraseology and Techniques:
http://www.faa.gov/air_traffic/publications/atpubs/aim/aim0402.html#aim0402.html.1
List plenty of other languages persay that we are to use. Perhaps these things aren't written out clearly in the FAR's but they go beyond saying and are in understanding.
AIM 4-2-1-B:
"The single, most important thought in pilot‐controller communications is understanding. It is essential, therefore, that pilots acknowledge each radio communication with ATC by using the appropriate aircraft call sign. Brevity is important, and contacts should be kept as brief as possible, but controllers must know what you want to do before they can properly carry out their control duties. And you, the pilot, must know exactly what the controller wants you to do. Since concise phraseology may not always be adequate, use whatever words are necessary to get your message across. Pilots are to maintain vigilance in monitoring air traffic control radio communications frequencies for potential traffic conflicts with their aircraft especially when operating on an active runway and/or when conducting a final approach to landing."
The chapter also mentions more than a few times that our judgment should be used to not congest the frequencies.
"Use discretion; do not overload the controller with information unneeded or superfluous."
