Moesan thank you for your comments. If I understand correctly your demonstration (is it your hypothesis or that of latinists ?), you state : uCe > ue > ɥi. I am not convinced by this hypothesis, because it does not satisfy the reductionism principle.
It would need to explain why 'e' became 'i' (e is it a closed vowel or a central vowel ?).
Moreover, it seems we can apply this hypothesis for some words like écuyer < scutarius, lui < illi, tuile < tegula.
At first, I thought it would be more easy to explain this evolution by a palatalisation phenomenon known in French (caballus > cheval), where 'k' would become 'j' in front of 'u', without to need to add a sequence combining 't' (as ok > oil > oui).
However, Hrvclv, we can exclude that hui would become from hodie, because it seems there is another word which has the same chain : ennuyer < inodiare.
The problem here is there are so many rules in order to demonstrate how ɥi would derive from Latin, but it is unreasonable.
Now, the only manner to explain that by one rule is to propose an epenthesis phenomenon or diphthongization in relation with syllabic rules and accentuation : u > y > ɥi (as in Italian : buono < bonus, in Spanish : bueno < bonus).
diphtongs are unstable sounds and vary very much between dialects; some common results in French have very different stories!
I have not phonetic signs at hand just now, so here /e/ is written /é/ (French), /j/ is written /y/(French, English only the semi-vowel), frontal /y/ written /ü/...
palatalisation in 'cabal' >> 'cheval' is an independant phenomenon: even today, some Oïl (Parisian) tendancy exists to prononce /k/ as /ky/ before central 'a'; it explains the chain (figurated signs, not IPA)
ka>> k'a>> kya>> tcha >> sha (shë) ('ë' = atone 'e') -
'buono', 'bueno' (some Spanish northern dialects have had 'uo' or 'uö', before opening of the diphtong (by stress) to 'ue' /wé/: it's an opening diphtong with no link to palatalisation.
in 'hodie' , yes, the 'e' is the close frontal vowe /é/l, already close enough to 'i' - but I think the 'i' was accentuated (stressed), so the subsequent 'e' fallen down. All the way, 'ui' in 'nuit' has an other history than the 'ui' in 'hui'!!!
+ 'u' never diphtonged into 'ui' in French ! It never diphtonged at all nor did 'i' - it's 'o' and 'e' which did.
the stressed latin suffixe '-arius', if I don't mistake, gave a chain (proxi!) >> -ari >> air >> -ér >> -ié(r) >> -yé (not in all dialects of Oïl: you can find '-é' in place of '-yé', '-i' too: so I think 'scu
tarius' >> '(è)skü
dary >> èskü
(dh)air >> é(h)kü
é(r) >> ékü
ié(r) >> éküi
yé (if epenthesis, it occurs here only because of the opening diphtong
ié, nothing to do with the preceding
ü << u
- 'tuile' from 'tegula' seems to me an inversion : te(gh)ülë >> teülë >> tiül(ë) >> tiül >> tüil (cf breton 'teol' not #'toel'= "teals", a loan from latin)
if I find time I' ll see old books: today I found this, in accord with me: [h=3]Étymologie
[modifier le wikicode][/h]
(1333) Du latin
tegula (« tuile »), de
tegere, « couvrir ».
(Vers 1290) tieulle (Vers 1170) tiule.