S at the end of Present Active Participle Pronunciation

Question

I've noticed that we tend to pronounce the "s" at the end of present active participles (e.g. navigans) as /z/. But in ancient Roman times, would it really have been pronounced this way, /nawiganz/, or /nawigans/?

Answer 1

final -ns being /nz/ occurs exclusively in anglicized Latin pronunciation

What you noticed is a feature of English pronunciation of Latin. English speakers typically use a certain type of anglicized pronunciation when saying many scientific or legal terms taken from Latin, such as “homo sapiens”, “mens rea” or “stare decisis”. In that type of pronunciation, “ns” at the end of any Latin word (not just participles) is pronounced as /nz/, like in the English words “coins” or “pens”.

As far as I know, the habit of pronouncing Latin “ns” as /nz/ whenever it occurs the end of a word doesn’t exist for speakers of any language other than English.

The pronunciation with /nz/ is certainly not thought to have existed in ancient Roman times.

The pronunciation of S and NS in Classical Latin

As described in the answers to Is "s" between two vowels voiced or unvoiced?, Latin “s” is generally thought to have been the voiceless fricative [s] everywhere in ancient times.

It’s possible that [z] occurred as an allophone of /s/ before a voiced consonant (as in Smyrna, cuiusmodi, eiusdem, or transmarinus). But it's not likely that [z] was used at the end of a word after a voiced consonant: we know from ancient descriptions that the consonant written b in words such as urbs and abs was pronounced as [p], which indicates that word-final s did not as a rule assimilate to [z] when preceded by a voiced consonant sound.

Ancient writers on pronunciation say that a vowel before ns or nf is always long. Based on this and also on the frequent tendency for n to be dropped in the cluster ns, modern linguists have theorized that at a certain point Latin ns was pronounced as [s] preceded by a long nasalized vowel. In W. Sidney Allen's Vox Latina, Allen argues that by the Classical Latin era, the nasalized vowel in this context had in fact been replaced by either a plain (non-nasalized) long vowel, or in educated speech, by a long vowel followed by a nasal consonant [n]. Other linguists consider a nasalized vowel stage to have existed at the time of Classical Latin. However, the exact phonetic and phonological properties of this nasalized vowel pronunciation are not clear.

This means that the reconstructed Classical Latin pronunciation of nāvigāns would be [ˈnaːwɪɡaːns] (if we follow Allen) or [ˈnaːwɪɡãːs] or perhaps something like [ˈnaːwɪɡa͜ãs] (if we follow the nasalized vowel reconstruction). There is also some debate on the phonetic details of Classical Latin vowel qualities.