Is "s" between two vowels voiced or unvoiced?

Question

I am phrasing the question as an absolute though I am well aware that the answer could be "we don't know" or "depends on your pronunciation."

I often hear church choirs pronounce miserere with a voiced "s," much like English /z/. The same goes for words like visio, occasio, and (even) causa. Perhaps since I take most of my pronunciation cues from Spanish, I tend to pronounce all these words with an unvoiced /s/ sound.

• Do we know, or have a good guess, about how this was pronounced classically?
• Are there established pronunciations that have rules about when and when not to voice "s"?

Answer 1

Two reasons for thinking that intervocalic S was voiceless in Classical Latin are:

1. Such S's originate from geminate [ss] (since single [s] was rhotacized, see jknappen's answer), and in fact we know that as late as the early Imperial period they could still be written SS, e.g. caussa. Such spellings are attested in inscriptions and mentioned by grammarians, e.g. Quintilian, who says (Inst. Orat. 1.7.20) that Cicero and Vergil spelled such words with SS. This suggests that the geminate pronunciation -- which presumably was always voiceless -- may still have been used at that period.
2. Evidence from Romance languages: in Romanian and in south Italian dialects intervocalic S is still voiceless to this day. Since voicing followed by devoicing is unlikely (though not impossible -- as sumelic points out in a comment, this in fact happened in Spanish), S was presumably voiceless in the varieties of Latin ancestral to these languages.

That said, voicing of intervocalic fricatives is very common cross-linguistically, so it wouldn't be surprising if it occurred sporadically or even regularly in some varieties of Latin -- there must have been plenty of phonetic variation across the vast stretch of time and space in which Latin was spoken -- but it seems not to have been a feature of the standard language.

Answer 2

Allen in Vox Latina (pp. 35–36) is pretty clear on this: they were unvoiced.

But it is most important to note that, unlike the English s, it stands for a voiceless consonant in all positions; it is not voiced between vowels or at word-end as in English roses (phonetically [rouziz]). Thus Latin causae is to be pronounced cow-sigh, NOT cow's eye. There are admittedly tendencies to voicing intervocalic s in the Romance languages, but these are of late origin.

He gives evidence for this, including pointing out that in Greek transcriptions, the Latin intervocalic s is always transliterated with a sigma, not a zeta, even though zeta had the sound of [z] in the Roman period.

Concerning what jknappen wrote, Allen continues:

In very early times intervocalic s had generally developed to voice [z], but this sound was not maintained in Latin and was changed to r (cf. Latin genitive plural -arum beside Sanskrit -asam and Oscan -azum).

_{(emphasis mine)}

(Cf. Jane Stuart-Smith's Phonetics and Philology, p. 52.)

So while intervocalic s in Old Latin was pronounced like our English z, it was still written as s.

As to when in Romance languages it changed, after the third century, for sure, since Gothic still borrowed Caesar as Kaisar. It seems actually rather late considering not all Italian languages have a voiced intervocalic s where others do (look at the casa/cazo example).

Answer 3

As TKR's answer says, the consensus seems to be in favor of reconstructing all intervocalic "s" in Classical Latin as voiceless: [s]. (I have seen some speculation about the exact place of articulation of this consonant: since it didn't contrast with any other sibilants, some authors suggest it was, or at least could be, somewhat "retracted": see the Wikipedia article on the voiceless alveolar fricative.)

With regard to Church pronunciation/"ecclesiastical" pronunciation/sung Latin, I haven't found a clear, established consensus. (Which is not unusual, in my experience—"ecclesiastical" Latin is not really a single standard since it is pretty much based on Italian pronunciation, which itself varies between different locations, and many people using this pronunciation nowadays aren't native Italian speakers. It's hard to find good resources giving detailed decriptions of Ecclesiastical Latin pronunciation, as opposed to impressionistic stuff intended to allow singers to get it approximately right. I also haven't found consensus about the height of "e", "ae/æ", and "oe/œ" as /e/ vs. /ɛ/ in this variety of Latin.)

Some sources say things like "never z as in raise" (SUNG ECCLESIASTICAL LATIN (ROMAN) PRONUNCIATION GUIDE, in rehearsal notes from the website of James F. Daugherty at the University of Kansas).

But it seems like some people do use /z/ for at least some intervocalic "s", and maybe /gz/ for at least some intervocalic "x", in sung Latin, as you have noticed. See the following thread on the Latin Discussion forum: Church-type pronunciation. Also see the following document which uses the wishy-washy description "when it comes between two vowels, it is closer to the sound of 'z' but softer, like the 's' in 'misery' " (Latin Pronunciation Guide). If we're talking about a native English pronunciation of "misery", that's what an English speaker would just call /z/.

"Ecclesiastical Latin", by Andrew Crow (Chapter 4, The Use of the International Phonetic Alphabet in the Choral Rehearsal, edited by Duane Richard Karna) even describes the following odd pattern of usage:

s is never voiced. That is, [s] not [z]
Some sources make an exception for borrowed words—especially Jesu as [jɛ zu] rather than [jɛ su]. Either version is acceptable in this case. (p. 40)

I don't know if a native Italian speaker would instinctively pronounce all intervocalic "s" in Latin as /z/. I know that in some varieties of Italian—including the one that is as far as I know most often regarded as being "standard"—intervocalic single "s" can actually correspond to either voiceless /s/ or voiced /z/ depending on some complicated factors, and there is a fair amount of variability in contemporary Italian accents. Wikipedia's "Italian Phonology" article says

[s] and [z] [...] can only contrast between two vowels within a word. According to Canepari,^[16] though, the traditional standard has been replaced by a modern neutral pronunciation which always prefers /z/ when intervocalic, except when the intervocalic s is the initial sound of a word, if the compound is still felt as such: for example, presento /preˈsɛnto/^[17] ('I foresee', with pre meaning 'before' and sento meaning 'I see') vs presento /preˈzɛnto/^[18] ('I present'). There are many words in which dictionaries now indicate that both pronunciations with /z/ and with /s/ are acceptable. The two phonemes have merged in many regional varieties of Italian, either into /z/ (Northern-Central) or /s/ (Southern-Central). Geminate /ss/ can be pronounced as single [s].

Another related discussion thread: Latin: S or Z between two vowels?, on Choral Net, which provides some more examples of equivocal descriptions like "Not "z" nor "s", blend the sound" and "a z-ish s". Apparently, this wishy-washiness is present in some edition of the Liber usualis.

Answer 4

Classically, there were (probably) only unvoiced s's. Preclassically, there were voiced /z/ segments in Latin, even written with the letter Z (at that time the 6th letter of the alphabet, where now the G sits). Those /z/ segments were shifted to /r/ (a process called rhotacism) and traces of that process are left in irregular declination patterns like honos, honoris (later regularised to honor, honoris).

The letter Z was officially removed from the Latin alphabet in the 3rd century BCE, because it was not needed at that time. It was some centuries re-introduced at the end of the alphabet to write Greek loanwords. It wasn't used for native Latin words at that time.