There are several categories, which are the wide areas separated by gray bars: Sailing & Encounters, Combat, Boarding Actions, Town UI, Repairs, and Reputation. Then each category has six variants (see at the top where it says Variant 1 - Variant 6?). These are just for flavor, so you don't hear the same sentence every time the event happens. Finally, many categories have three Alternates. These are lines that play if the same event happens twice in a short period of time. So if a ship appears on the horizon, you might hear "Sir, there's a ship on the horizon." But if a second ship appears right away, you'll then hear "We've sighted another ship, sir." Not all categories have alternates, because you won't hear dialogue like "Sir, we're sinking!" twice in less than a minute. When a category doesn't have an alternate, I block out those cells in the spreadsheet with gray so I know I don't have to write those.