There are some verbs in English that people (understandably) can find confusing, and I think near the top of that list is lie/lay.

So let’s outline the problem. We have one verb that is intransitive (i.e. it does not take a direct object)—that would be “lie.” So: “Today I lie down; yesterday I lay down.”

Then we have “lay,” which is transitive. In other words, it can take an object. So we say, “Today, I lay the book down; yesterday I laid the book down.”

What’s so confusing about these two verbs is that the past tense of one (lie/lay) is the present tense of the other (lay/laid). How did that happen?

Well, that happened because these two verbs are actually historically related to each other. If we go all the way back to Old English (the English of “Beowulf”), we find that there are two general classes of verbs, both of which in Old English were “regular” verbs. There’s one class of verbs that forms the past tense by changing the internal vowel. So: ring/rang, swim/swam, lie/lay. And we still have some of those in English, although we now think of them as irregular: there are so few of these verbs left that we can no longer see the systematic pattern for how they make the past tense. (A good number of these verbs died, and others became regular verbs: for example, the past tense of help used to be holp but now is helped.)

The other kind of verb in Old English takes a “d” sound, what we now often think of as “-ed,” to form the past tense. So: talk/talked and lay/laid.

In Old English, there are some intransitive verbs, like lie, that have related “-ed” verbs that can be used transitively (or causatively). To lay something down is to cause it to lie down. This is why the past tense lay (intransitive) looks identical to the base for the transitive verb lay (whose past tense is then laid).

When in doubt, just remember that if there’s an object, it will be lay/laid. And if there’s no object, and you just want to take a nap, it’s lie/lay. (But if you lay yourself down to sleep, it is lay, not lie, because there is an object there: yourself. There’s always a twist!)

What about you? Do you get confused by the lie/lay quandary? What other word confusions do you find interesting, funny or annoying? Share your thoughts in the comments section.

This video originally appeared in LSA Today.