How should the name Cæcilius be pronounced in Latin?

The way I was taught, at an English public school from 1963 to 1970, this is how I would have pronounced it:

The same as your teacher said I think...

initial C like K in kill
ae to rhyme with eye
c like the k in kill again
illi to rhyme with filly
u as in push or full
s as in sea

To my ear, Mel Gibson is wrong to pronounce Latin as if it was modern Italian. It is quite common in movies though.

No one really knows for sure just how ancient Romans pronounced many of their words. So today two different traditions have emerged. In English, we tend to follow the Germanic model which has 'c' pronouned as a hard 'k'. Some other European languages prefer a more Romance pronunciation, making the 'c' a 'ch' sound. (To my ear, the Italian 'ch' sounds much more likely than the hard K sound.) Some languages follow neither model and prefer to render the 'c' vocally as a 'ts' sound. Go figure.

It depends on the era in which the word or name was used. The Classical Latin alphabet was very phonetic, each letter represented one sound, by and large, so there wasn't the ambiguity that is found in written English. "C" always represented the /k/ sound.

The name Cæcilius is an ancient Latin name dating at least since the Classical period. It appears in Cicero's writings. He lived during the first century B.C.

In accordance with Classical Latin writing, the name Cæcilius would have been pronounced approximately like your first instance: Ky-keel-ee-us (Ky to rhyme with eye).

During the Middle Ages shifts in Italian and English pronunciation eventually changed /k/ to the /tʃ/ (as in church) sound, and in English eventually to /s/, so that "c" before "e" and "i" came to be pronounced /s/.

By the Middle Ages then, the name Cæcilius came to be pronounced Ky-cheel-ee-us in Italian, and Ky-sill-ee-us in English.

I found this to be a pretty good article.
Latin Pronunciation Demystified

I try to avoid questions of pronunciation. I learned Latin in an
ecclesiastic context and that is the pronunciation that sounds
"right" to me. If i read Latin, that is the way I pronounce it in
my head.

So I would say Chay-CHEEL-ee-oos and earn the scorn of true
Classicists.

Yeah, I'm more comfortable with the Medieval Church pronunciation as well, even though I took my Latin lessons in a public school where the Classical model was taught.

In Latin class we were told that Caesar was to be pronounced "Ky-sar"

I was taught the same thing. Later on I came to think of that as silly.

Many thanks for all of your help.
Interesting suff.

Are there no existing books on language from the classical period (like dictionaries, books on linguistic style, pronunciation, grammar, etc)? Those Romans seem to have written everything down - surprised that there is nothing from which we can glean pronunciation.

There is plenty. If you are interested you a good starting point would be Vox Latina (W. Sidney Allen, Cambridge University Press 1965) Despite the title, it's in English!

There are several main sources of knowledge:

The Latin alphabet was meant to be entirely phonetic. Unlike us, the ancient Romans did not inherit their spellings from any earlier language. What you see is what you get.

Language teaching was big business in Roman times, and ancient Roman grammarians give us surprisingly detailed information about the sounds of the language.

Languages derived from Latin give us a lot of evidence. In fact, many of the letters of the alphabet are pronounced the same way in French, Spanish, Portuguese, and Italian. It stands to reason that the original Latin pronunciation has survived.

Spelling errors made by the ancient Romans are very informative. If two letters are often mixed up, they must sound fairly similar. Likewise, if two letters are never mixed up, we know they sounded different.

Here’s an example: In classical times, the natives had no trouble keeping ae distinct from e; if they ever misspelled ae it came out ai. Later on, they started changing ae to e. That enables us to pinpoint when the sound of ae changed.

Finally, transcriptions into other writing systems, such as Greek and Sanskrit, often pin down the ancient pronunciation of Latin very precisely.

I suppose you refer to the classical Latin here.
However, music (though not exactly the classical period) has a lot to do with pronunciation of Latin - the missals showed the pronunciation for singing the texts.
That, however, wasn't the original form. There are a few more books to that mentioned by contrex (the second edition of Voy Latina is from 1978).
Marcus Fabius Quintilianus aka Quintilian wrote a twelve-volume textbook on rhetoric entitled Institutio Oratoria which gives some hints on the pronunciation ...

I want to add that past-Roman times inscriptions in Latin (e.g. from the the 5th/6th century onwards in Germany, England etc) 'show' the different sounds as well.

Cecilia is quite an old name, btw, starting with Caecilia Metella Cretica (daughter of Quintus Caecilius Metellus Creticus) in the second half of the first century over Saint Caecilia (second century) until today. (There are quite a few Cecilias in the medieval time and later as well)

Thanks Walter. I know the name Cecilia is old. I meant modern in the sense of in current use (Caecilius is not). The point I meant to raise with this modern name was that of the way the letter cs in it are pronounced (ch) and whether or not this could be a clue as to how the ancient masculine version of the name was pronounced.

In our parts of the world, the name, as it appears in the personages of St Cecilia, etc., is usually pronounced as Sesilia. I find it hard to believe the Romans ever pronounced c as s.

In your parts, certainly. We've got here in Germany hundreds of choirs, calles "Cäcilia ....", my late mother's name was Cäcilia ("Cecil"), and that's usually pronounced this way.

Interesting - with a ts.

As far as the Romans were concerned, however, going on what the pros on this thread have suggested, the c was pronounced as k in classical Latin.

Very interesting to see that, in German, the a umlaut has been preserved. As I understand it, this letter stands for ae, which the guys here assure us was pronounced like the word eye in English.

So, at one stage in history, your dear old mum would have been called Kykilia.

Funny how language evolves!

But its derivative, Cecil, certainly is.

Such a cool name. I'm calling my kid that. Old school.

Alas, there is no version of this name in modern Italian (a hypothetical Cecilio). The way Cecil is pronounced must be a million miles from the Roman pronunciation, which is what I was after.

Actually, the "ä" in Cäcilia isn't really an Umlaut but more the transcript of a (wrong) Latin pronunciation.