Here are a few words that are used in air traffic control



ACKNOWLEDGE “Let me know that you have received and understood this message.”
APPROVED “Permission for proposed action granted”
BREAK “I hereby indicate the separation between portions of the message.”
(To be used where there is no clear distinction between the text and other portions of the message.)
BREAK BREAK “I hereby indicate the separation between messages transmitted to different aircraft in a very busy environment.”
CANCEL “Annul the previously transmitted clearance.”
CHECK “Examine a system or procedure.”
(Not to be used in any other context. No answer is normally expected.)
CLEARED “Authorized to proceed under the conditions specified.”
CONFIRM “I request verification of: (clearance, instruction, action, information).”
CONTACT “Establish communications with…”
CORRECT “True” or “Accurate”.
CORRECTION “An error has been made in this transmission (or message indicated). The correct version is…”
GO AHEAD “Proceed with your message.”
Note.- Not used whenever the possibility exists of misconstruing “GO AHEAD” as an authoization for an aircraft to proceed. The phrase “GO AHEAD” may be omitted and, in its place, a response made by using the calling aeronautical stations’s call sign followed by the answering aeronautical stations’s call sign.
HOW DO YOU READ “What is the readability of my transmission?”
I SAY AGAIN “I repeat for clarity or emphasis.”
MAINTAIN “Continue in accordance with the condition(s) specified” or in its literal sense, e.g. “Maintain VFR”.
MONITOR “Listen out on (frequency).”
NEGATIVE “No” or “Permission not granted” or “That is not correct” or “Not capable”.
OVER “My transmission is ended, and I expect a response from you.”
Note.— Not normally used in VHF communications.
OUT “This exchange of transmissions is ended and no response expected.”
Note.— Not normally used in VHF communications.
READ BACK “Repeat all, or the specified part, of this message back to me exactly as received.”
RECLEARED “A change has been made to your last clearance and this new clearance supersedes your previous clearance or part thereof.”
REPORT “Pass me the following information…”
REQUEST “I should like to know…” or “I wish to obtain…”
ROGER “I have received all of your last transmission.”
Note.— Under no circumstances to be used in reply to a question requiring “READ BACK” or a direct answer in the affirmative (AFFIRM) or negative (NEGATIVE).
SAY AGAIN “Repeat all, or the following part, of your last transmission.”
SPEAK SLOWER “Reduce your rate of speech.”
STANDBY “Wait and I will call you.”
Note.— The caller would normally re-establish contact if the delay is lengthy. STANDBY is not an approval or denial.
UNABLE “I cannot comply with your request, instruction, or clearance.”
Note.— UNABLE is normally followed by a reason.
WILCO “I understand your message and will comply with it.”
(Abbreviation for “will comply”.)
WORDS TWICE a) As a request: “Communication is difficult. Please send every word, or group of words, twice.”
b) As information: “Since communication is difficult, every word, or group of words, in this message will be sent twice.”