I couldn’t give a toss about non-native speakers. If I went to Spain I would either happily suck it up, or if it caused me that much of a problem I’d learn the language.
I think there's a lot of waffle in announcements which smack of a manager somewhere trying to sound clever. This does nothing to help anyone whose English isn't great.
"Inclement weather" is an example. There's people whose first language IS English, who don't know what that means!
There's enough waffle about what tickets are and aren't valid, without even more waffle about a whimsical description of the possible friction coefficient of platform surfaces being deficient in anything less than a nice day. Just use plain English. "Platforms may be slippery."
Overuse of the word 'service'. I've heard it reference the actual train, but also refer to the tea and biscuit distribution on a trolley for first class passengers as well; and also the buffet "open and cleared for service" like it's had permission from Air Traffic Control, rather than just "open".
Worst of all: "This is an empty service" on platform screens when the train is empty to the depot - and so "not (even) in service"!
Nonsense!
All of which make life difficult for people whose first language isn't English. I agree announcements might not need dumbing down, but we do need to think more carefully about if announcements are clear and simple.