For the sake of simplicity and ease of vocabulary acquisition, I will use articles in my notes below. This is based on my own experience; however, I have included references at the end.
il pane (m.sing) - the bread, mainly used in the singular form to talk about bread generally
i pani (m.pl) - sometimes used to refer to different types of bread, though i tipi de pane would still be more common in this context.
il panino (m.sing) - the roll, the bread roll, the filled roll or sandwich
i panini (m.pl) - the rolls, the bread rolls, the filled rolls or sandwiches
un panino al prosciutto - a ham roll
i panini al formaggio - the cheese rolls
il panino imbottito - the filled roll (like a sub or British idea of a panino)
i panini imbottiti - the filled rolls (subs, panini)
il sandwich (m. sing) - the sandwich (a typical sandwich made of white bread, cut into triangles)
i sandwich (m.pl - invariable) - the sandwiches
(sometimes seen written as i sandwiches though)
un sandwich aperto - an open sandwich
il tramezzino (m.sing) - the sandwich (sandwich made with sliced bread)
i tramezzini (m.pl) - the sandwiches
" i migliori 20 pani italiani": http://www.dissapore.com/grande-notizia/i-migliori-pani-italiani-regione-per-regione/
(you may want to learn a bit more Italian before trying to read the article!)
http://www.collinsdictionary.com/dictionary/english-italian/roll http://www.collinsdictionary.com/dictionary/italian-english/panino http://www.collinsdictionary.com/dictionary/english-italian/sandwich http://www.garzantilinguistica.it/en/search/?q=sandwich http://www.garzantilinguistica.it/en/search/?q=tramezzino
As you can see from the link to the 'best Italian breads', there is a huge amount of regional variation in Italy, not just in terms of food, but also in terms of language and culture. Therefore, depending on where you are, you may find variations on this. However, if you can remember this vocabulary, you should have no problem making yourself understood.
Buona fortuna et buon apetito!
(if anyone notices any errors, please let me know - my eyes have glazed over after all that!)
Google Translate correctly translates sandwiches to panini, but when I enter "sandwich" it gets translated to... sandwich. However, if I click on the word and look at the alternate answers, "panino" is in there. So who knows? Hopefully someone who sees this comment and can clarify it for us!
There's no need to be embarrassed - you are correct. Un panino is indeed a roll. This needs to be added to the list of correct translations, so please report it if you get caught out again.
In England it is NOT a mistake. We say "paninis". It's become an English word. But paninis are different to sandwiches which are made with flat slices of bread rather than bread rolls. In fact here in England the whole field of bread with fillings is so complicated you will need to come and live here for at least a year before you get it straight!
If I held up a picture of you and convinced a nation of people you're name was Samantha would that make it true? If they then saw you walking down the street and called you Samantha, kept doing this for weeks, would that make it true? If you were to pull an apple out of your pocket and call it a burrito, would that give burrito a new definition in British English? No. It's just ignorance. Widespread ignorance is still ignorance. Even if paninis was an official, accepted word in English, it wouldn't matter, because we are learning Italian and in Italian paninis IS NOT A WORD!
Yeah, we definitely should. And to all the other pedants, the English plural of "panini" (which in English is a singular word, no matter how incorrect that is in Italian) is "paninis". I take it you don't call pizzas "pizze" and pasta "paste"? Because if you don't, you're hypocrites.