Your location says you're in Belgium?
In which case, no need to much about with the internet - just get hold of a VHF scanner and a chart and listen to the local en-route RT.
Pleasantries in local languages are normal. I'll generally greet French controllers with "**** radar, bonjour, this is G-ABCD", or words to that effect. Most countries will do a small amount of local language conversation with local traffic.
But, my experience en-route in Belgium and Germany is that those two countries have consistently some of the most clear and correct English on RT. They're unlikely to lead you astray.
Whilst the UK has a few national differences also, this book is free online and covers all of the basic principles extremely well...
https://publicapps.caa.co.uk/modalap...detail&id=6973
The main non-standard things in the UK are the names of "services" (Basic, traffic, etc.), the rest is pretty much universal and will work anywhere.
G