Okay, I am far from a Starbucks expert, but here’s a little help for Starbucks-phobes who want to branch out but are scared by the menu. I second the suggestion to go in at an off-peak time, because that way you won’t be stressed out by the pressure of the people standing behind you waiting for you to make up your mind.
First, sizes. You can get short (very small, aka kids’ size), tall (small), grande (medium), or venti (large). In my experience, if you order by saying “small”, “medium” or “large”, you will not be mocked or harassed, but you might be asked, “Did you mean the 16 oz size?” or whatever.
On to drinks. You can order plain coffee. Really, you can. Moving on from there, you can order espresso-based drinks. A latte is espresso and steamed milk. A cappuccino is espresso, steamed milk, and a whole bunch of froth. You can also have them put a shot of flavored syrup in your drink, or chocolate syrup, or caramel.
An americano is espresso and hot water.
You can also order just a plain steamed milk, with or without flavored syrup in it. I think this is called a “steamer” but I’m not sure. I get it for my kids sometimes.
Crazy stuff you might hear people order sometimes: “Upside down” means the espresso and whatever all else goes in the opposite order of the way it usually does. “Split shot” means half regular, half decaf. I would point out that while it is fine to use the Starbucks lingo if you are hip to it, it would also be perfectly fine to simply order “half regular, half decaf” as well. The way I know all of this stuff is that I asked the employees at Starbucks, and they told me, very politely and with no sneering in evidence.
I don’t know anything about macchiatos or frappucinos or whatever, because I don’t order them, but there have been some pretty good descriptions of what they are in this thread. And if I have screwed anything up, I am sure that one of our resident baristas can easily correct my info.