Idle Rambler recently asked if I was going to include a note on Latin pronunciation. I hadn't planned to, but it is a self-evidently good idea, so here goes. This is what my Liber Usualis has to say about it.
Vowels and Diphthongs
Each vowel has one sound; a mixture or sequence of sounds would be fatal to good Latin pronunciation; this is far more important than their exact length.
It is of course difficult to find in English the exact equivalent of the Latin vowels. The examples given here will serve as an indication; the real values can best be learned by ear.
A is pronounced as in the word Father, never as in the word can. We must be careful to get this open, warm sound, especially when A is followed by M or N as in Sanctus, Nam, etc.
E is pronounced as in Red, men, met; never with the suspicion of a second sound as in Ray.
I is pronounced as ee in Feet, never as i in milk or tin.
O is pronounced as in For, never as in go.
U is pronounced as oo in Moon, never as u in custom.
Y is pronounced and treated as the Latin I.
The pronunciation given for i, o, u, gives the approximate quality of the sounds, which may be long or short; care must be taken to bring out the accent of the word. e. g . mártyr = márteer.
As a general rule when two vowels come together each keeps its own sound and constitutes a separate syllable. e. g . diei is di-e-i; filii is fi-li-i; eórum is e-ó-rum.
This applies to OU and AI : e.g. prout is pro-oot; coutuntur = co-oo-toon-toor; ait is ah-eet.
But notice that AE and OE are pronounced as one sound, like E above, e.g. caelum.
In Au, Eu, Ay the two vowels form one syllable but both vowels must be distinctly heard. The principle emphasis and interest belongs to the first which must be sounded purely.
El is similarly treated only when it occurs in the interjection : Hei = Hei, otherwise Mei = Me-i, etc.
U preceded by Q or NG and followed by another vowel as in words like qui and sanguis, keeps its normal sound and is uttered as one syllable with the vowel which follows : qui, quae, quod, quam, sanguis. But notice that cui forms two syllables, and is pronounced as koo-ee.
The consonants must be articulated with a certain crispness; otherwise the reading becomes unintelligible, weak and nerveless.
C coming before e,ae,oe,i,y is pronounced like ch in Church. e. g . caelum = che-loom; Cecilia = che-chee-lee-a.
CC before the same vowels is pronounced T-ch. e. g . ecce => et-che; siccitas = seet-chee-tas.
SC before the same vowels is pronounced like Sh in shed. e. g . Descendit = de-shen-deet.
Except for these cases C is always pronounced like the English K. e. g . caritas = kah-ree-tas.
CH is always like K (even before E or I). e. g. Cham — Kam, machina = ma-kee-na.
G before e, ae, oe, i, y, is soft as in generous. e. g. magi, genitor, Regina. Otherwise G is hard as in Government.e. g. Gubernator, Vigor, Ego.
GN has the softened sound given to these letters in French and Italian. e. g. agneau, Signor, Monsignor. The nearest English equivalent would be N followed by y. e. g. Ah-nyoh, Regnum = Reh-nyoom; Magnificat = Mah-nyee-fee-caht.
H is pronounced K in the two words nihil (nee-keel) and mihi, (mee-kee) and their compounds. In ancient books these words are often written nichil and michi. In all other cases H is mute.
J often written as I, is treated as Y, forming one sound with the following vowel. Jam — yam; alleluia = allelooya; major = ma-yor.
R: when with another consonant, care must be taken not to omit this sound. It must be slightly rolled on the tongue v. g. Carnis. Care must be taken not to modify the quality of the vowel in the syllable
preceding the R: e. g. Kyrie: Do not say Kear-ee-e but Kee-ree-e; Sapere: Do not say Sah-per-e but Sah-pe-re; Diligere: Do not say Dee-lee-ger-e but Dee-lee-ge-re
S is hard as in the English word sea but is slightly softened when coming between two vowels.
e. g. misericordia.
TI standing before a vowel and following any letter (except S. X. T.) is pronounced tsee.
e. g. Patientia — Pa-t-see-en-t-see-a. Gratia = Gra-t-see-a. Constitutio = Con-stee-tii-t-see-o. Laetitia = Lae-tee-t-see-a.
Otherwise the T is like the English T.
TH always simply T . Thomas, catholicam.
X is pronounced ks, slightly softened when coming between two vowels, e. g. exercitus.
XC before e, ae, oe, i, y - KSH. e. g. Excelsis = ek-shel-sees.
Before others vowels XC has the ordinary hard sound of the letters composing it. e. g. K S C excussorum = eks-coos-so-room.
Y in Latin is reckoned among the vowels and is sounded like I.
Z is pronounced dz. zizania = dzee-dza-nee-a
All the rest of the consonants B, D, F, K, L, M, N, P, Q, V are pronounced as in English.
Double Consonants must be clearly sounded e. g . Bello = bel-lo, not the English bellow
Examples : Abbas, Joannem, Innocens, piissime, terra.