Is it "The case' closure" or "The case's closure"? How exactly do I pronounce it?

  • Full sentence, please.
    – user3169
    Nov 29, 2015 at 0:28
  • Is it "The case' closure" and "The case's closure"?
    – user26973
    Nov 29, 2015 at 0:29
  • 1
    There's no reason to ask for a full sentence here. The answer would be the same regardless.
    – user230
    Nov 29, 2015 at 0:48
  • 2
    By the way, I tried to write a very general ("canonical"?) answer here, so ideally we can either close other questions about the pronunciation of the possessive suffix as a duplicate of this one, or we can at least use this answer as a reference. I've been meaning to write this for a while, since we've gotten other questions like this one, but we didn't really have a good general answer to them.
    – user230
    Nov 29, 2015 at 2:44

1 Answer 1


The possessive suffix has three pronunciations. Which one you use depends mainly on what the last sound is:

  • /ɪz/, following sibilants (the six sounds /s/, /z/, /ʃ/, /tʃ/, /dʒ/, and /ʒ/)
  • /z/, following voiced sounds other than sibilants (including vowels)
  • /s/, following voiceless sounds other than sibilants

You might have noticed that these rules are exactly the same as the rules for pronouncing the regular plural suffix -(e)s. But the possessive suffix is a little more complicated, because sometimes it isn't pronounced at all.

  • When it is pronounced, it's typically written 's.

  • When it's not pronounced, it's typically written '.

So how do we know when to pronounce it?

If the word ends in a sibilant and falls into one of the following categories, the possessive suffix is not pronounced, and is therefore written with just an apostrophe:

  1. Regular plurals:

    boys' /bɔɪz/
    cats' /kæts/

    In these examples, the /z/ and /s/ are already there as part of the plural suffix -e(s), so we don't have to add another (and indeed shouldn't).

  2. Irregular plurals where the plural affix itself is regular (for example leaf, where the base changes to leave, but the plural affix is regularly pronounced /z/):

    leaves' /liːvz/
    knives' /naɪvz/

  3. In certain fixed expressions:

    for goodness' sake
    for conscience' sake

  4. In Greek names of more than one syllable:


One more rule: If a name ends in a /z/ sound, it may or may not be pronounced:

Dickens's OR Dickens'
Jones's  OR Jones'
Burns's  OR Burns'

But although both versions work, people tend to say the former and write the latter more often.

Your example is the word case, pronounced /keɪs/. It ends with an /s/ sound, which is a sibilant, one of the six sounds listed at the top of this answer. That means we write the possessive 's and we pronounce it /ɪz/, making the possessive form case's /keɪsɪz/.

For more information, see A Comprehensive Grammar of the English Language, p.320. Most of my examples and rules are drawn from this book. Additional discussion can be found in The Cambridge Grammar of the English Language, p.1595. (Please note that the possessive form is often called the genitive form in linguistics, and technical references may use that term instead.)


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