Etymology and pronunciation of words ending in “-iasis”

Question

Unfortunately, I don’t own any Latin or Greek dictionaries or etymological texts, but I tried to research this topic on the internet. Here is what I found:

Perseus: words ending in “iasis” in L&S mostly have short -ăsis

Long ā:

• ănăthȳmĭāsis

Short ă:

• ĕlĕphantĭăsis, mydrĭăsis, phthīrĭăsis, hypŏcŏrĭăsis, sătyrĭăsis, sīrĭăsis, plătycŏrĭăsis, stĕnŏcŏrĭăsis, trĭchĭăsis

Oddly, all of them are transcribed with a short “a” in Latin except for “anathymiasis”.

“Short a” is also implied by the antepenultimate stress in the usual pronunciations of English words with this ending (e.g. English “satyriasis” = /sætəˈraɪəsɪs/), so this doesn't seem to be just a Lewis and Short thing.

OED: but they're from Greek words with -ᾱσις?

The Oxford English Dictionary (OED) has a entry that, if I’m reading it correctly, says that the vowel was long in Greek:

-asis, suffix

Etymology: < Latin -ăsis, Greek -ᾱσις.

Forming names of diseases, really nouns of state or process from verbs in -άειν (contracted -ᾶν); as from ϕθείρ louse, ϕθειρᾶν to be lousy, ϕθειρίᾱσις phthiˈriăsis; so elephantiasis, psoriasis, and many modern words, more or less analogical, as allantiasis, arseniasis, etc.

There is also the following note in the OED about a historical pronunciation of “myiasis” (not in Lewis and Short) with penult stress:

N.E.D. (1908) gives the pronunciation as (məiˌiˌēi·sis) /maɪɪˈeɪsɪs/.

The length of the alpha in some of the above words in Greek seems to be supported by some Ionic spellings with η listed in LSJ on Perseus: “μυ^δ-ίησις” (for mydriasis) and “σα^τυ^ρί-ησις” (for satyriasis). (Wikipedia tells me that “Proto-Greek ā > Ionic ē; in Doric, Aeolic, ā remains; in Attic, ā after e, i, r, but ē elsewhere.”)

Questions

• What is the Greek etymology of this apparent suffix -ιασις? I think that I recognize the last part as the nominalizing suffix -σις from PIE *-tis. But I'm confused by the -ια-. The OED says verbs were a step in the derivation of these words, and gives as examples psoriasis (ψωρίασις) and phthiriasis (ϕθειρίασις). But the corresponding verbs are apparently ψωριᾶν and ϕθειρᾶν: one has an iota before the ᾶν and the other doesn't. Why does ϕθειρᾶν turn into "ϕθειριασις" instead of "ϕθειρασις" (if the OED's explanation is right)?

• Was the alpha long in Greek? I found a few pages through Google Books that seem to say that in general, Greek nouns ending in ασις could have short /a/ or long /aː/, with a rule for choosing between them based on the conjugation of the verb from which they are derived (long when derived from verbs in -αω; short elsewise) (Introduction to Greek Prosody, Peter Wilson; Practical rules for Greek accents & quantity, by Philipp Buttmann). Unfortunately, the citation forms used by the OED for ϕθειρᾶν and ψωριᾶν don't end in -αω, and I don't know how to conjugate verbs in Greek so I can't tell if they have this ending in other forms.

• Why are most of these words pronounced with "ă" in Latin, except for "ănăthȳmĭāsis", according to Lewis and Short?

I'm really stumped. I did come up with one tentative hypothesis, which is that these words were late borrowings that were stressed on the antepenult after the Greek (like certain nouns in -ia were stressed on the penult after Greek in Romance languages; e.g. Spanish filosofía < Gr. φιλοσοφία). If that's the case, maybe it would be better for L&S to say that they belong to a period of Latin after vowel length began to be lost, rather than transcribing the "a" with a breve? But I'm not confident about this. I'd really appreciate an explanation if anyone knows of one.

Answer 1

Pronunciation

Below you can see the vowel lengths marked by L&S and by OLD. Note that OLD doesn't cover post-Classical vocabulary.

(In this table L&S = the online L&S via Perseus; OLD = the 1st edition of the OLD consulted by hand; Gaffiot = the 2016 online edition via Logeion.uchicago.edu.)

Vowel in penultimate syllable

|---------------------|------------------|------------------|------------------|
|                     |  Lewis & Short   |Oxford Latin Dict.|    Gaffiot       |   
|---------------------|------------------|------------------|------------------|
|   anathymiasis      |       long       |     long         |     long         |
|   elephantiasis     |       short¹     |     uncertain²   |     short        |
|   mydriasis         |       short      |     long         |     short        |
|   phthiriasis       |       short      |     long         |     long         |
|   hypocoriasis      |       short      |     (no entry)   |     short        |
|   satyriasis        |       short      |     (no entry)   |     (no entry)   |
|   siriasis          |       short      |     long         |     long         |
|   platycoriasis     |       short      |     (no entry)   |     long         |
|   stenocoriasis     |       short      |     (no entry)   |     (no entry)   |
|   trichiasis        |       short      |     (no entry)   |     short        |
|---------------------|------------------|------------------|------------------|

¹There's a less common variant noted with long "o" replacing the short "a".

²Explicitly stated by OLD to be of uncertain length.

So, L&S tells us that the "a" in these words is short, with the exception of "anathymiasis". The Oxford Latin Dictionary tells us the "a" is long for all the words it knows about. Gaffiot has a mixture.

On the English pronunciations, I would hesitate to infer anything about Latin vowel lengths based on English pronunciations (even older ones, where these can be confirmed). These would rely on English speakers being aware of the correct Latin vowel lengths in the first place. I would not be confident this was ever the case, even in the period when Latin was widely studied.

For "mydriasis", the OED online gives four pronunciations: Brit. /mʌɪˈdrʌɪəsɪs/, /mᵻˈdrʌɪəsɪs/, /ˌmɪdrɪˈeɪsɪs/, U.S. /məˈdraɪəsəs/. So only the third of these has an English long "a" /eɪ/ - but if you consult an earlier edition of the OED (1989) the sole pronunciation given is with long "a": mɪdrɪˈeɪsɪs. On the other hand, "satyriasis" and "siriasis" have long "i", short "a" both in today's OED and the 1989 edition.

Greek

As you point out, the OED gives the suffix "-asis" the etymology "Latin -ăsis, Greek -ᾱσις", showing a short Latin "a" and long Greek alpha, and the OED goes on to describe the suffix as follows:

Forming names of diseases, really nouns of state or process from verbs in -άειν(contracted -ᾶν); as from ϕθείρ louse, ϕθειρᾶν to be lousy, ϕθειρίᾱσις phthiˈriăsis; so elephantiasis, psoriasis, and many modern words, more or less analogical, as allantiasis, arseniasis, etc.

Both in the etymology and in this passage the OED identifies the Latin vowel as short (phthiriăsis, where the Oxford Latin Dictionary has long "a"). (The OLD was completed in 1982 and is a much newer work than L&S. Where L&S and the OLD differ, I would tend to believe the OLD, at least in terms of Classical usage, which is the period that the OLD covers. Much of the OED was written long before the OLD was available, and OED editors most likely relied on L&S in many cases.)

Looking up some of the words at lsj.gr, the forms given for Greek are with long alpha: https://lsj.gr/wiki/%CF%86%CE%B8%CE%B5%CE%B9%CF%81%CE%AF%CE%B1%CF%83%CE%B9%CF%82 ("Full diacritics: φθειρίᾱσις"); https://lsj.gr/wiki/%CF%83%CE%B1%CF%84%CF%85%CF%81%CE%AF%CE%B1%CF%83%CE%B9%CF%82 ("Full diacritics: σᾰτῠρίᾱσις").

Originally the Greek suffix simply denoted nouns of state, but it came to be associated in particular with medical conditions (at least in Latin and English use).