As I was reading the other day, I came across the phrase speeded up. By now you know my affinity for words and all things word related, so you’ll understand my reaction of sitting bolt upright. Not only did the phrase not sound correct, I don’t believe I’ve ever seen it used that way nor have I used it myself. Naturally, this sent me to the laptop to check in with some of my favorite grammar websites.
As it turns out, neither sped nor speeded is more correct as they are both standard variations of the verb to speed. In many old English reference books, the rule is that speeded works only in the past tense phrasal verb speeded up such as I had read. What I found amusing is that I usually lean toward those archaic/dated words and phrases, but obviously not in this particular instance.
Today writers use what they think sounds best. Speeded is often used without up whereas sped is used with up or alone. Also, sped is more common than speeded these days which, according to some sites, makes it the safer choice. In either case, be consistent when writing.