Indeed, truncations to unstressed elements are “not supposed to happen”. But they do, which makes me think of several things.

One is something I’d tentatively call Aggressive Footing*, as long as Philip (uh, Lip?) doesn’t mind this bit of terminology: processes that require feet may create them. Eric’s example is the footing of the truncated {chris}topher as [tofər]. Topher wasn’t a foot before truncation, but it sure is after.

This is not so different from truncating Albert, Robert, and other N-bert names as Bert. None of us would say that Robert is two feet, bert being one of them, but it’s a foot after truncation. A trickier case is Alonzo > Zo, since it’s debatable whether the last syllable is a foot ([o] being one of the vowels that can be unstressed and unreduced when word-final – as in Rico, another attested nickname for Eric).

A third and odd case is a crowd cheer from the 1972 USSR vs Canada “Summit Series”, the precursor to the Canada Cup and now World Cup of Hockey. In the original series, the partisan Canadian crowds would yell Da, Da, Canada! Nyet, nyet, Soviet!. Not exactly a truncation of Canada to Da, but about as close as you can get. And the word “Canada” in this cheer gets (aggressively) two feet.

And our other diagnostic for foot structure, expletive infixation, can encourage Aggressive Footing too. It’s only “supposed” to go between two feet, and where it doesn’t, the stranded elements acquire feet of their own anyway. Look what happens when you say “Chris-fuckin-topher”, “Alon-fuckin-zo”, or “Cana-fuckin-da”. Feet on either side that weren’t there before.

I also think Aggressive Footing is in a relationship of counter-counter-feeding ordering with both expletive infixation and hypocoristic truncation, since a later rule creates foot structure that an earlier rule failed to provide. But if anyone asks which rule counter-counter-feeds the other, I will shudder.

* After Hammond’s Aggressive Morphology and Zuraw’s Aggressive Reduplication.