（レストランやカフェで店員さんを呼ぶ時の）すみませんって英語でなんて言うの？

You must attract the waiter's attention or ask someone to help.

Excuse me is a polite way to ask for assistance from someone.

Sometimes instead of just saying "Hi" I say "Hi there" so that I can get a specific person's attention. Or saying "Hi there, excuse me" usually alerts the waiter that you are trying to get someone's attention rather than just speaking to someone else.

Hello! - to grab the servers attention, normally they should come straight over apologize and answer your request. Excuse me, we have been waiting! - This will tell the servers that you are not impressed, and psychology tell them to look after you better. I would only use this if the waiting time has been unreasonable. Can we have the bill please? Can you take our order please? If a server is walking past and you manage to stop them this is the best thing to say.

example "excuse me". or "excuse me waiter". or "excuse me waitress". In a restaurant or cafe the term waiter or waitress is used. If you are in a store or shop the term would be assistant. Then you can just say "excuse me please".

Excuse me (their name here).'' can be used to call your server over to you.

If you would like to call a waiter or waitress, your communication will be short and loud enough to hear from wherever you are seated or standing. Make sure to have eye contact or a hand lightly raised. Assistance: help, "Hi there, please get me another glass of water with ice."

"Excuse me" is a causal term used in many contexts, in this context you can use it to get someones attention, for example in a restaurant or bar, to summon/call a waiter over you are able to say 'excuse me' as it is a polite expression of getting someones attention, also you can use 'Hello' to get someones attention.