Heard on NPR’s Morning Edition this morning, in a segment on sleepwalking: 14-year-old Miranda Kelly reporting a moment when she realized, “Oh, I sleptwalked.”
That’s double inflection, on both parts of the verb sleepwalk, where the standard form (sleepwalked) has inflection only on the second part, the head V walk.
There are plenty of similar examples to be found, with PST and PSP (slept), marked PRS (sleeps), and PRP (sleeping):
[PST] I slept walked to the toilet and woke up pooping. Easily one of the most disorienting events of my life. (link)
[PST] I think I sleptwalked last night (link)
[PSP] What reasons cause people to sleepwalk?
My brother tells me that I stood up in the middle of the night last night and that every time he asked me something all I said was “nothing” and after a couple of questions I laid down an went back to sleep. I’ve sleptwalked a lot in my life. I’m 18 and I can remember being a kid and my parents telling me that I sleepwalk. (link) [note BSE in to sleepwalk and unmarked PRS in I sleepwalk]
[marked PRS] My boyfriend sleeps walks and has hit me in his sleep? How can I help him? (link)
[marked PRS] Miley Cyrus sleeps walks! (link)
[PRP] My Friend Is Sleeping walking Help?
can u tell me y she is sleeping walking and how long it will last and what should i do im scared to wake her up (link)
[PRP] Perhaps this is also by design as the entire society is sleeping walking into a soft kill carnival. (link)
Background: the verb sleepwalk (or sleep-walk) is a back-formation from the N + N synthetic compounds sleep-walking ‘walking in one’s sleep’ and sleep-walker ‘someone who walks in their sleep’; OED2′s first cite is from 1923 (sleep-walks), with a similar cite from 1954 and cites for sleepwalked in 1976 and 1981. In any case, sleepwalk is a V of the form N + V, so it’s inflected on its V (second, head) portion.
Another piece of background: there are cases where V + N expressions, which would of course have inflection on their V (first, head) portions (this is often called “internal inflection”), sometimes alternatively have inflection on the V + N as a whole (“external inflection”), so that inflectional morphology is realized on their N (second) portions. In this posting, I looked at the case of dragged/hauled ass vs. drag/haul assed:
Both internal and external inflection are attested for drag/haul ass, with the former clearly more frequent.
For N + V combinations, internal and external inflection would normally be indistinguishable, since the head is also the final element. But in addition to internal and external inflection, double inflection is also attested; for drag/haul ass:
In fact, there’s a third attested variant: double inflection, as in dragged/hauled assed and dragging/hauling assing.
In these cases, ass is not being treated as a V — it’s still a N — but it gets inflectional suffixes because it’s at the end. In contrast, in the doubly inflected sleptwalked etc., sleep is treated as a V, right up to the non-default PST/PSP slept.
That is, some people seem to have reanalyzed N + V sleepwalk as a V + V compound, which would then be eligible for (exceptional) inflection on the first V as well as on the second (head) V.
English isn’t rich in V + V compounds; the example most commonly cited is stir-fry. From OED2:
trans. Chiefly in Chinese cookery: to fry (meat, vegetables, etc.) rapidly on a high heat, while stirring and tossing them in the pan. [also attributive in things like stir-fry cooking]
The cites (from 1959 on) have the verb in BSE (stir-fry), PSP (stir-fried), and PRP (stir-frying) forms, and marked PRS (stir-fries) occurrences are easy to find — all with head inflection only. But some speakers have opted for double inflection, as in these examples:
[PSP] Dak galbiis a spicy stirred-fried chicken dish that is quite appetizing with intense flavors. All ingredients are stirred fried in a large pan placed in the center of the table as this dish is more of a crowd-pleaser, ample enough for a quartet of diners to share. (link)
[PSP] Jin’s Kitchen: stirred fried collard green (link)
[marked PRS] This Is A Typical Spicy Hot Chinese Dish That Stirs Fries Marinated Pork In A Spicy Sauce. (link)
[PRP] Trying Stirring Frying (link)
(Some of these come from non-native speakers, but not all.)
Once again, there’s a (distinct minority) tendency to allow double inflection.