Hi Chas,
Aeronautical radio is probably the worst technical quality transmission in existence. Apart from being generated in the noisy environment of an aircraft cockpit, it uses AM. This is one of the most interference prone transmission medium in use at the moment.
The only way the system works is that everyone tries to use the standard phraseology, as per
CAP 413. That way the people listening to the transmission know what is coming next.
Apart from the poor technical quality there is also the jargon. Some of this dates back to the time when Morse was the only communication method. Things like QNH for altimeter pressure setting etc.
After a while you will find that you get used to the poor quality and the jargon. A common problem for pilots is the fear of messing up on the radio. If you listen on the frequencies of some of the larger airports you will find that everyone has off days on the radio. No one worries too much as long as the message gets through.
If you have a lot of spare time, you might like to look at the
ATC Humor Thread. It's mostly about RT transmissions that went wrong.
Safe Flying,
Richard W.