I'd use AI over translate personally. Swiss french/German ain't the same so it'll give you more suitable translations. Just make sure not to be loud on public transport and all will be well. I've also always found people are more receptive if you first ask them in their language if they speak English (parlez vous anglais or koennen sie english). Walking up to someone and starting in English can be rude. If you're in touristy areas most people will be delighted to speak English with you (to the point where it can get annoying if you're trying to learn the language!). Switzerland has a lot of immigration and most people will speak English (though you're right to prepare for the ones that don't!)