The Real Meaning of Io Evohe!

The phrase "Io Evohe" is used very commonly in Wicca, on loan from the western mystery schools. For a long time, I thought these were just "barbarous words." A little research showed they are not. I got curious if there was a translation for this phrase.

Barbarous words are made up of seed sounds strung together to create nonsensical words. We sometimes say nonsense because the sounds have a transformative nature on the mind of the speaker as a result of the particular vibrations the sounds make. Sound can transform the mind. This can be true particularly with the names of some deities, which can be chanted to modify your inner self.

The first word of the phrase is very simple. It is the Latin translation of the Egyptian, Isis, goddess of fertility.

The second word is a bit more complex. Collins English Dictionary tells us that "evohe" is a variant of "evoe," which is "an exclamation of Bacchic frenzy."

As is common when transcribing from Latin to a Germanic language, the original upsilon (u), which was often represented by the character we now know as a "v," stayed intact but was likely misunderstood. So we need not hold tightly to the spellings we can read above.

On the website, Hellenicgods.org, is an article revealing all of the many names of Dionysus. A particular entry stands out (highlights mine).

Évios - (Euius; Gr. Εὔιος, ΕΥΙΟΣ) Évios is an epithet of Diónysos referring to the ecstatic howl of joy, εὐαἵ, εὐοἱ, made by the God and those who worshipped him and participated in his orgies.

- Lexicon entry: Εὔιος (Εὔἱος EM391.15, cf. Lat. Euhius), ὁ, name of Bacchus, from the cry εὐαἵ, εὐοἱ, in lyr. passages; Εὔιος, = Βάκχος.  II. εὔιος, ον, as Adj., Bacchic. (L&S p. 717, left column, edited for simplicity.)- "Cornutus, the tutor of the Roman poet Persius (ed. 34-62 BCE), tells us that the wine treaders invoked the God by various names, such as 'Bakchos' and 'Euios.' [Cornutus, Theologiae graecae compendium XXIX.] Reference to these scenes was made at the Second Council of Constantinople, the Trullianum, in the year 691 A.D. Until that date the wine treaders still cried out 'Dionysos,' but this was now forbidden. [μἡ τὸ τοῦ βδελυκτοῦ Διονύσου ὄνομα τοὑς τὴν σταϕυλὴν ἐκθλίβοντας ἐν τοῖς ληνοῖς ἐπιβοᾶν, cited by P. Koukoules, Βυζαντινῶν βίος καὶ πολιτισμός , p. 293.]"  (Dionysos: Archetypal Image of Indestructible Life by Carl Kerényi, 1976, Princeton Univ. Press. p. 67) 

- (ed. Évios is a) name of Dionysos, implying, Well done, my son! words ascribed to Zeus, when he saw Bacchus returning victoriously from combating the Giants. Evoe, or Evan, was the exclamation with which the Bacchanals invoked their God during the celebration of his orgies. (CM*p.181)

The invocative shout mentioned above didn't just fall into obscurity. In 1903, Ginn & Company published Allen and Greenough's New Latin Grammar for Schools and Colleges by J. B. Greenough, G. L. Kittredge, A. A. Howard, Benj. L. D'Ooge, Ed. The names of both deities above are cited as interjections of joy (highlights mine).

INTERJECTIONS
[*] 225. Some Interjections are mere natural exclamations of feeling; others are derived from inflected parts of speech, e.g. the imperatives em, lo (probably for eme, take); age, come, etc. Names of deities occur in herclē , pol(from Pollux ), etc. Many Latin interjections are borrowed from the Greek, as euge, euhoe, etc.

[*] 226. The following list comprises most of the Interjections in common use:—
ō, ēn, ecce , ehem, papae , vāh (of astonishment).
iō, ēvae, ēvoe, euhoe (of joy).
heu , ē˘heu, vae, alas (of sorrow).
heus, eho, ehodum, ho (of calling); st, hist.êia , euge (of praise).
prō (of attestation): as, prō pudor, shame!1 Some of these have been included in the classification of adverbs. See also list of Correlatives. § 152.

I should note that the Order of the Golden Dawn was gaining popularity in Britain and America in 1903. No other occult organization had as much impact on the contemporary witchcraft movement as did the Golden Dawn. The majority of the ritual concepts that are used today were codified and transmitted by the Golden Dawn.

By shouting "Io Evohe," a witch is effectively shouting, as an exclamation of joy, the names of a female and male fertility deity, "Isis! Bacchus!" Now you (and I) can put one of thousands of witch questions to bed.

Update: It was brought to my attention that all of this may not help those who want to bother with original pronunciation. For those who don't, it is always acceptable to pronounce this phrase traditionally, which is "EE-oh ee-voh-HAY."

Both Latin and Greek had a series of rules for establishing which syllable was stressed. Usually, the "penultimate" (second to last) syllable was pronounced unless it had a short vowel in it. In that case, the emphasis shifted to the "ante-penultimate" syllable (next to the second to last, that is, the third to last). There were always exceptions that put the emphasis on the last syllable.

In the case of "Io," there are only vowels present. Though some vowels create diphthongs, there is no diphthong for i+o, so these are separate syllables. Using the rule above and Latin pronunciation gives us "EE-oh." This is assuming the Latin O comes from the Greek omega, rather than the Greek omicron. If it was originally an omicron, the name could be spoken as "EE-aw" rhyming with the phrase "Be off."

The other name could have several pronunciations. Church Latin pronounced V as a V, while classical Latin pronounced it as W. Also, the use of H is interesting. In Greek, the H is the vowel Eta, which sounds like "eh." Interestingly, this word has another spelling, which drops the H to become "evoe." This could be a clue that the original word was Greek and the H was the Eta, rather than the breathy letter we know in English. This means the vowel, eta, immediately precedes a diphthong of "oe." All of these vowels blend into a sound that is kind of like "oy,"  This would make the pronunciation something close to "EY-voy" or "EY-woy" depending on your preference for either the modern or the classic Latin pronunciation.