I don’t think I’ll have much new to add:
Having been through a couple of airports in foreign countries where I don’t speak the language, I still managed to find my way around. Arrive a few minutes early, relax, get your bearings, then start looking around. Signs are everywhere, there are almost always some uniformed airline personnel in sight. Ask for help finding whatever you need. Getting through security will always be a pain, for anyone. Once you get to the gate, go up front to the gate agent and let him or her know that you have trouble understanding the boarding announcements and you’d like someone to flag you down when they get ready so you can be prepared. As busy as gate agents get, they do seem to really appreciate a kind word and the opportunity to really help someone vs being yelled at or complained to about something outside their control.
I’m just going to toss this out there. but if all those sounds are causing extra stress or anxiety, maybe remove your aids? You can do this without them.
On board the aircraft there’s another set of problems. There are exit row seats you probably shouldn’t take if you can’t hear or understand spoken instructions. Also, the flight crew is required to give a safety briefing. Even though most people ignore it, if you do think it’s something important enough to hear, then you need to mention something to a flight attendant when you board. They’ll help out, and then if there is an announcement they’ll come by and let you know what was said, so you don’t have to worry about missing anything important.
Relax, it will all be OK.