In short, galumph fails the rule since it is no better than onomatopoeia. I don't care that Lewis Carroll coined it, or that it is "probably an alliteration of gallop" or "to gallop triumphantly". The fact that it came from the nonsense poem, Jabberwocky, belies it's true nature, and were I to deign to engage in this "word", I might one day find myself discussing the origins of "doh" or "psst".
But as long as I'm on a rant about DD's posting of utterly useless non-words which are barely more than onomatopoeia, I'll add a brief archival posting about:
Now, unlike other words, which I had never heard of before, but now own, sough has no real usefulness except to describe this particular sound of wind through something (hence the rustling AND sighing requirements). I can hardly say that Moses und Aron would require any voice to sough, although we did chant, sing off pitch, and wail. I almost wish we were required to sough as I think it would have been a lot more sonorous in places. I don't think this works. What a bizarre little word, with a bizarre etymology, and an even more bizarre choice of pronounciations. When did we lose the "w"? and why? and what does "swogan" mean??? DD got a little lax here. If I were to read my DD rantings aloud, would they only sound like so much sough to the uneducated or uninitiated ear? Better (and probably). And if I really wanted to describe the wind, a metaphor works so much better than some obscure word. "The whisper of the breeze through the leaves" creates so much more useful imagery than just sough. And when do you have occasion to want to make both a rustling/sighing sound of wind that you wouldn't describe what you wanted outright? A conductor would never tell the percussion section to make the sound of sough. That would be useless, on so many levels. He'd just say, he wants more rustling and sighing, like the whisper of a breeze through leaves. Perhaps I'm just being supercilious about the word sough.