Illustrator has a helpful feature: ToolTips. If you hover your cursor over a tool for a moment, a little yellow box of text pops up telling you what the tool is. If the tool has a keyboard shortcut, that shortcut appears in parentheses after the name.
ToolTips, despite their name, don’t work with tools alone. (And they don’t give you tips — just the names of things. Go figure.) They work just about anywhere in Illustrator that you can position a cursor. ToolTips give you information about whatever the cursor is over. Hover over a color swatch, and the ToolTip tells you the name of that color. Hover over a brush, and it tells you the name of the brush. Not sure what a cryptic icon in the Pathfinder palette means? Just let the ToolTip tell you.
ToolTips are invaluable whenever you’re using the program because there are just too many things to remember. With ToolTips, you don’t have to!
To turn ToolTips off or on, choose Edit→Preferences→General and select (check) or clear (uncheck) the Show ToolTips check box.