Unlike consonantal i, u normally occurs singly between vowels, e. g. caue. But in the Greek words Euander, Agaue, euoe, the u represents a double [w] (as in Greek), so that although the preceding vowel is short, the syllable is heavy.
I think that means that au or eu should not be treated as diphthongs in these cases. In modern spelling, it would be consequent to use v instead of u here.
I have looked up these and some similar words in the most reliable dictionaries:
AGAVE: Agauē in ThLL, Agauē and Agāvē in Lewis/Short, Agāvē in Gaffiot 2016 and Georges
APOSCOPEVON: aposcopeuon in ThLL, aposcopeuōn in Lewis/Short, Gaffiot 2016, and Georges
CATASCEVA: catasceua in all four dictionaries
EVANDER: missing in ThLL (the proper nouns supplement only covers A–D so far), Euander and Ēvander in Lewis/Short, Gaffiot 2016, and Georges
EVANGELISTA: euangelista in ThLL, Gaffiot 2016, and Georges, euangelista and ēvangelista in Lewis/Short
EVOE: euoe in ThLL, euoe and ēvoe the other three dictionaries, with Lewis/Short treating ēvoe as “less correctly”
MNEVIS: missing in ThLL, Mnēvis in the other three
PARASCEVE: parasceuē in ThLL and Georges, parascēvē in Lewis/Short, parasceūē in Gaffiot 2016 (the u macron might mark a diphthong or be a typing error)
As we can see, the dictionaries are far from consequent. ThLL seems always to use u in these cases, although it uses modern spelling in cases like caveo etc. The other dictionaries use varying spellings. Note also that the long vowels always marked before v contradict Allen's statement.
The problem for the hyphenation patterns is, which spellings should be supported, especially if the v spelling should be supported, even if none of the dictionaries does use it and if different hyphenations for the u and the v spelling are acceptable or necessary with respect to modern pronunciation.
The test lists contains the following hyphenations:
A-pos-co-peu-on
A-pos-co-pe-von
ca-ta-sce-va
Cle-vas
Cra-te-vas
Eu-œ-nus
E-væ-i
E-va-gon
E-va-go-ras
E-van-der
e-van-ge-lis-ta etc.
E-van-thes and several similar entries beginning with E-v
W. Sidney Allen states (Vox Latina, p. 42):
I think that means that
auoreushould not be treated as diphthongs in these cases. In modern spelling, it would be consequent to use v instead of u here.I have looked up these and some similar words in the most reliable dictionaries:
As we can see, the dictionaries are far from consequent. ThLL seems always to use u in these cases, although it uses modern spelling in cases like caveo etc. The other dictionaries use varying spellings. Note also that the long vowels always marked before v contradict Allen's statement.
The problem for the hyphenation patterns is, which spellings should be supported, especially if the v spelling should be supported, even if none of the dictionaries does use it and if different hyphenations for the u and the v spelling are acceptable or necessary with respect to modern pronunciation.
The test lists contains the following hyphenations:
A-pos-co-peu-onA-pos-co-pe-vonca-ta-sce-vaCle-vasCra-te-vasEu-œ-nusE-væ-iE-va-gonE-va-go-rasE-van-dere-van-ge-lis-taetc.E-van-thesand several similar entries beginning withE-v