And though guttural don't exist in english, dutch goed (g is guttural) is related to english good (g is velar), here I didn't know what guttural meant, beware that it happens sometimes, for I dig very wide field, I am occasionally misinformed here & there, and I don't have an institution making fact-checking, yet. anyway, dutch g is not far from english h in hot, but h-kind has some other name, but I don't operate these terms yet, and I will show that ipa definitions are not only different from ones ancient linguists had, but also sometimes wrong, as I explain only in volume 2 (ctrlF it for trapezoid) so råw the structure of this book still is, I add this grey text here, after I'm past 769.4 kB of html alone in volume2.) or am I overcomplicating the matter? both variants were correct to the extent: Guttural speech sounds are those with a primary place of articulation near the back of the oral cavity. In some definitions, this is restricted to pharyngeal consonants, but in others includes some velar and uvular consonants. Guttural sounds are typically consonants, but some vowels' articulations may also be considered guttural in nature.
and being now in the bidst of volume3, I found this book:
Wadell, L.A.: 1927, The Aryan Origin of the Alphabet, Luzac & Co, London
http://library.umac.mo/ebooks/b33333282.pdf (mirror)
in which I found an incredibly interesting paragraph in Aryan Origins of Alphabet:
It was long ago noticed that in the Phœnician, Greek and Latin or Roman alphabets there is a repeated sequence of the letters as vowels, labials, gutturals and dentals. This sequence is well displayed by Professor Petrie, in arranging the letters on a square table like the old "Horn-book" board for teaching children their ABC.
So they also called it guttural, even being published in english. So it looks like two different phonetic schools fighting with each other over this classification. And who knows how deep in the past they go.
(I just copied this piece from vol.3, it goes further and deeper there, though you're not recommended to read that far, though I felt like bringing this exact piece, because it's a masterpiece, an unique so far source speaking of this subject, and doing it as if everybody knows it "It was long ago noticed" duh)
good thing is I go much deeper, and that axial symmetry I explain position of Y & Ω with seems to be unknown even more thoroughly. but of course I still want to see where it was noticed even longer ago. Sir Petrie was an egyptologist, and I suspect the roots of alphabet somewhere in Egypt (read about it further in this volume)

The End of the secret level.