An interesting dilemma:
I’m writing something in which it makes sense for me to use the past tense of the verb “sleepwalk.”
The easiest approach is of course to treat “sleepwalk” as a compound verb the first element of which is a noun and the second element of which a verb, like “babysit.”
And yet “sleepwalked” looks and sounds and feels so totally wrong.
I feel an incredibly strong compulsion to understand “sleep” here as a verb, which makes no linguistic sense, since at least off the top of my head I can’t think of any compound verbs both elements of which are verbs, but still. In this theoretical idiolect I generate the past tense “slepwalked.” (I tried “sleptwalked” but that was just barbaric.)
Of course I could get around the whole problem by using “somnambulated,” but where would be the fun in that?