In "(X)egg", I asked,
Also, why does Spanish huevo have an h- absent from Latin ovum and its other descendants (e.g., Portuguese ovo, French oeuf, and Italian uovo)?
David Boxenhorn sent me a link to the answer:
The letter H is always mute [in Spanish]. It is written [...] orthographically [but not etymologically] in initial hue- (in the traditional graphic there was not distinction between U and V and writing without initial h- could suggest the reading ve-), cf.:
hueso (<= L. ossum) bone, huevo (<= L. ovum) egg;
So h was a consonant letter that indicated the absence of a consonant phoneme (i.e., /v/).
龚勋 Gong Xun independently sent me the same solution and reminded me about how Spanish hu- stands for /w/: e.g., in Nahuatl [ˈnaːwatɬ] (in Nahuatl pronunciation).
All this made me realize why French huit 'eight' has a nonetymological h-. Wiktionary confirmed my guess:
From Old French uit, from Latin octō, the h was added to avoid confusion with vit.
But I still don't understand what's going on with 'egg' in Iranian:
Indo-Iranian: *āwya-(ka-)*Indic: Sanskrit vi- 'bird'
Iranian (no Proto-Iranian form at Wiktionary)
h- (Baluchi, Kurdish, Zazaki)
Ø- (Avestan, Khotanese, Ossetic)
y- (Khwarezmian; y- was added "irregularly" to initial ā- according to Henning 1977: 489)
Did some dialect(s) of Proto-Iranian develop an initial x/h-?
*2.17.4:51: I don't know how *-ka- can be reconstructed at the Proto-Indo-Iranian level since Sanskrit vi- 'bird' doesn't contain the suffix -ka-. Is there an Indic reflex of *āwya-ka- that I don't know? Or is *āwya-(ka-) a Proto-Iranian rather than a Proto-Indo-Iranian reconstruction?