Pronouncing the Letter S  

The letter S can present some difficulties for pronunciation because of the variety of sounds it can make. Most often, it produces two distinct consonant sounds: /s/ and /z/. In some specific instances, S can also form the sounds /ʃ/ (as in sure) or /ʒ/ (as in usual). We’ll briefly touch on these pronunciations as well, but first we’ll focus on the /s/ vs. /z/ sounds.

Determining which of these two possible pronunciations to use is very tricky because many words that have very similar spellings can have S pronounced as either /s/ or /z/, with very little indication as to which is correct. For instance, the noun goose is pronounced /gus/, while the verb choose is pronounced /ʧuz/; from the spelling alone, we can’t tell why one is pronounced /s/ while the other is pronounced /z/.

While in many instances we simply have to memorize pronunciation oddities like these, there are some conventions that we can follow to help us determine which sound to make. This largely depends on where S appears in the word—at the beginning, the end, or in the middle.

The pronunciation of S is the easiest to remember when it is the first letter of a word: it is almost always pronounced /s/, regardless of whether it is followed by a vowel or another consonant; it is never pronounced /z/. For example:

However, when S is followed by H, the two letters form a digraph that produces the sound /ʃ/, as in:

There are also two specific exceptions in which S creates the /ʃ/ sound on its own when it is followed by the vowel U: sugar (/ˈʃʊgər/) and sure (/ʃʊr/).

Finally, it should be noted that there are quite a few consonant letters that never or almost never follow S at the beginning of words: B, D, F, G, J, R, V, X, and Z. The only exceptions are a few foreign loanwords—such as svelte (/svɛlt/) from French (meaning “gracefully slender” or “sophisticated”).

The letter S can serve several different functions at the end of words, each of which can influence its pronunciation. Here, we’ll look at when the inflectional suffixes “-s” and “-es” are used to form plural nouns and third-person singular verbs, when “-s” follows an apostrophe to form a possessive or a contraction, and when S appears naturally at the end of a word.

Nouns are usually made plural by adding “-s” or “-es” onto the end, without changing the spelling of the base noun itself. In the same way, we add “-s” or “-es” onto verbs to indicate actions done by a singular person or thing being described in the third person. Fortunately, the rules for pronunciation of both plural and third-person “-(e)s” are relatively straightforward. (Many words can function as both nouns and verbs, depending on context, so our examples will include both since the pronunciation rule applies to each in the same way.)

S is always pronounced /s/ when it comes after an unvoiced, non-sibilant consonant sound—that is, after /k/, /f/, /p/, /t/, and /θ/ (the sound usually associated with TH). We always add a single “-s” after these sounds, never “-es.”

For example:

Whenever the inflectional suffix “-s” is added to a word ending in a voiced consonant sound (/b/, /d/, /g/, /l/, /m/, /n/, /ŋ/, /r/, /ð/, /v/) or a vowel sound, the S will be pronounced as /z/. When adding “-s” to a word that ends in a voiced or unvoiced sibilant speech sound (/s/, /z/, /ʃ/, /ʒ/, /ʧ/, /ʤ/), we need to create an extra syllable to add clarity between the two sounds, so the suffix becomes “-es” and is pronounced /ɪz/. We also add “-es” to words ending in a consonant + Y (which is then changed to an I) and sometimes the letter O, but this does not create an additional syllable.

Let’s look at some examples:

(*Many words may be spelled either “-os” or “-oes,” sometimes with one spelling preferred over the other, or else being equally common. While this won’t affect the pronunciation of the word, be sure to check the dictionary if you’re unsure of the preferred or proper spelling.)

Many nouns ending in F or FE will have their spelling changed to VE when “-s” is added to make them plural. This isn’t always the case (as we saw from some of the examples earlier), but it happens quite often. When it does, the normal pronunciation rules apply and the added S is pronounced /z/. For example:

These are considered irregular plurals, and we simply have to memorize them. Go to the section on Forming Plurals to learn more.

Finally, it’s worth mentioning that the pluralization of several nouns ending in “-th” produces a similar effect. While the spelling doesn’t change at all, the pronunciation changes from /θ/ to /ðz/. For example:

When we indicate possession of a noun or form a contraction with the word is, we most commonly use an apostrophe ( ’ ) + “-s.”

While the rules regarding how to form possessives and contractions by using an apostrophe + “-s” are unique, the rules for how that S is pronounced are the same as what we’ve already seen for plurals and third-person singular verbs: S is pronounced /s/ when it follows unvoiced, non-sibilant consonants, and it is pronounced /z/ (or /ɪz/) when it follows voiced consonants, sibilants, and vowels. This rule also applies when apostrophe-S is used with proper nouns—that is, capitalized names of people, brands, companies, or places.

Let’s look at some examples of both possessives and contractions using apostrophe-S (for the sake of simplicity, we’ll only look at proper nouns for the possessives and pronouns for the contractions—with one exception):

While there are some consistent, reliable rules regarding the pronunciation of S when it is attached to a word, it’s a bit more complicated (and inconsistent) for words that naturally end in S (or S + silent E). However, there are still some conventions we can follow that are usually reliable.

Because we use the suffix “-s” to inflect nouns and verbs, we don’t usually have base words that end in a single S after a vowel or vowels. If the vowel makes a short sound, we typically double the S so it isn’t confused for a plural noun or a third-person singular verb.

Like words that begin with S, words that end in SS always make the /s/ sound. Note that this is not always the case when SS appears mid-word (which we’ll look at later), but it is always true at the end of words. For example:

This is a fairly reliable convention. If a word ends in a short vowel sound followed by /s/ (and it isn’t plural or in third-person singular), there’s a good chance that it will be spelled SS—and if you know the word ends in SS, then you can be sure it is pronounced /s/.

However, there are some exceptions. There are some words that end in a short vowel sound followed by /s/ but are only spelled with a single S. In particular, words with a short U sound (/ʌ/) at the end are often followed by a single S. Much less commonly, there are a few words that have a long vowel sound followed by SS. For example:

Finally, it’s worth noting that any adjective formed with the suffix “-ous” will be pronounced /s/ at the end, as in ambitous (/æmˈbɪʃəs/), enormous (/ɪˈnɔrməs/), hilarious (/hɪˈlɛriəs/), etc.

While we typically double S when it appears after a short vowel sound at the end of a word, when it comes after a long vowel sound, S is usually followed by a silent E.

Unfortunately, there’s generally no clear way to predict if S will have an /s/ or /z/ pronunciation in these words. The only time we can be sure of its pronunciation is when a word has the same spelling but has two pronunciations, one for a verb and one for a noun (or, in one case, an adjective). When this is the case, the noun form will be pronounced with a final /s/, while the verb form will be pronounced with a final /z/. (Note that this only applies to words that can be both nouns and verbs, and only when one of the sounds changed between them is the final S.)

There are many examples that we could list—too many to include here. Instead, we’ll just look a selection of some common words:

S can also create the last sound of a word when it follows four specific consonants: L, N, P, and R. Again, we must add a silent E after this S to avoid such words being confused with plurals or third-person singular verbs. Unlike when SE follows vowels, S is almost always pronounced /s/ in these words, even for words that function as both nouns and verbs.

For example:

(One notable exception to this convention is the word cleanse, which is pronounced /klɜnz/.)

The pronunciation of S in the middle of a word largely follows the patterns we’ve already seen when it appears at the beginning or end, taking the /s/ or /z/ pronunciation depending on whether it appears next to vowels or certain consonants. When it appears in the middle of a word, there are also two other sounds it can create: /ʃ/ or /ʒ/.

Mid-word, S most commonly comes between two vowels, but when it comes before or after a consonant, it most often appears before unvoiced consonant sounds (/f/, /k/, /l/, /p/, /t/) or the sibilant sound /ʧ/, or else after the voiced consonants /n/ or /r/. Next to these consonant sounds, S almost always forms the sound /s/.

For example:

(*The D is silent in handsome, so S still follows the /n/ sound and is still pronounced /s/.)

While this is a pretty reliable convention, there are some exceptions in which S is pronounced /z/ when it appears next to these consonants, such as:

(*S can also be pronounced as /s/ in these words, depending on local pronunciation.)

Except when it is at the end of a prefix attached to an existing base word or part of a compound word (in which case the individual words’ pronunciations take precedence), S does not often appear before or after voiced consonant sounds other than /b/, /d/, and /m/. However, while S can form the /z/ sound next to these consonants (especially /m/), it commonly produces the /s/ sound as well; unfortunately, we just have to know which way it is pronounced for individual words. For example:

(*The P in raspberry is silent.

**The D in grandson can also be silent.

***The initial D in Wednesday is silent.)

One instance in which S is always pronounced /z/ is when the letter combination SM appears at the end of a word (most often as a part of the suffix “-ism”), in which case a reduced vowel sound (the schwa, /ə/) is pronounced between S and M. For example:

When S appears between two vowel sounds in the middle of a word, it tends to create the /z/ sound, but it is by no means uncommon for it to be pronounced /s/, too. Unfortunately, there’s no clear way to be sure of whether S will take an /s/ or /z/ pronunciation in this position—we simply have to memorize individual words.

Here are some examples:

These two sounds are created when S is followed by certain letter combinations at the end of a word. In each case, the same combination can produce either the /ʃ/ or /ʒ/ sound, depending on the letter that precedes S.

When S is followed by the suffix “-ion,” it creates the /ʃ/ sound if S comes after L, N, or another S (with some exceptions);* if S comes after a vowel sound, it will make the /ʒ/ sound. When S comes after R, it is usually pronounced /ʒ/ (especially in American English), but it can also be pronounced /ʃ/. For example:

(*There are two words ending in SSION that can take either the /ʃən/ or the /ʒən/ pronunciation: fission [meaning “the splitting or breaking of one thing into two parts”] and scission [meaning “the act of dividing, cutting, or severing”]. The word rescission [which means “the act of rescinding”], on the other hand, is only pronounced /rɪˈsɪʒən/.)

S behaves in a similar way before the ending “-ure” as it does before “-ion”: when it comes after N and S, it produces the /ʃ/ sound; after vowel sounds, it produces the /ʒ/ sound. Unlike S + “-ion,” it does not come after L or R. And, of course, the word sure on its own can be pronounced /ʃʊər/ or /ʃɜr/.

For example:

(*One exception to this convention is the word erasure, which is pronounced /ɪˈreɪʃər/.)

Less commonly, S will be followed by the ending “-ual.” After the letter N, S is pronounced /ʃ/, while it is pronounced /ʒ/ after vowels:

Finally, there are a few words in which S is not pronounced at all. Some of these are foreign loanwords; others are the result of spelling adjustments made to English words throughout the years. Regardless of their origin, there are no indicators in these words that tells us the S will be silent; they are all just special exceptions that we must memorize.