When traveling abroad, Americans often come home with the impression that Europeans are rude. This is especially true of those who have gone to France. Actually, the problems occur when visitors act like they do at home.
In New York, if someone says, “Hey Mack! Got the time?” The time will probably be forthcoming. Things are different in Europe. Before you address a stranger, you must first ask their pardon, for interrupting them, and wait for an acknowledgment that they recognize your presence, and that they are willing to interact with you. In France, you would say, “Bonjour, pardon moi.” Then wait for them to speak. You don’t have to ask if they speak English, everyone in Europe learns to speak English in school. Most Europeans speak better English than many Americans. After they’ve answered, go ahead and ask them what you need to know. And, no, speaking slower and louder is not necessary.
Before you go, buy a phrase book for the language of whatever country or countries you plan to visit and learn the five magic phrases - Hello. Excuse me (Pardon me). Please (If you please). Thank you. Can you help me? Learn these, if nothing else. Of course the more of their language you can speak, the better off you’ll be. The main thing is to learn enough to show them you’re at least making an attempt to speak their language. That and a smile will make your trip much more enjoyable. Bon voyage.