Chapter 11.3: Phonemes

A phoneme is the smallest meaningful unit of sound.
The key word in this definition is meaningful. Although speech is continuous,
as we listen to someone speaking, we are able to break the words and phrases
into individual segments, to which we ascribe meaning. For example, we analyze
the word “pit” as composed of three distinct segments, each of which is a meaningful
phoneme: /p/, /ɪ/, and /t/, or simply /pɪt/. To signify that we are talking about
phonemes and using the IPA, we write the symbols between slashes / /. When we
discuss actual pronunciation, regardless of phonemic status, we use square brackets
[ ].

Minimal pairs

In order to determine if a sound is a phoneme, we can set up a pair of words in
which the only difference is one single sound. For example, take the word “pit”
again, written in IPA as [pɪt], and let us pair it with the word “bit”, in IPA
[bɪt]. These words differ by only a single sound, the first one;
there is the minimal amount of difference between the two words. Thus, we call
the set a minimal pair. Because we as English speakers can distinguish
the utterances [pɪt] and [bɪt] as two distinct words, we can determine that
/p/ and /b/ must have a meaningful
difference to us. This difference allows us to establish that /p/ and /b/
are both phonemes in English. Another way to think of the word “meaningful” is
as a contrastive difference. The sound /p/ has a contrastive difference from
other sounds such as /b/ or /t/ or /f/.

We can establish other phonemes of English in the same way, by taking a word
like “pit,” and changing it by one sound at a time. Take “pit,” and change the
first sound to “b”: “bit.” Now change the first sound to “h”: “hit.” Now change
the vowel to the “ee” sound: “heat.” Now change the last sound to “d”: “heed.”
Now change the first sound to “m”: “mead.” Now change the vowel to the long “a”
sound: “made.” And so on. You can see here that the spelling changes in
various unexpected ways, but if we write these words in IPA it is clearer that
only one sound is changing at a time: [pɪt] ~ [bɪt] ~ [hɪt] ~ [hit] ~ [hid] ~
[mid] ~ [med]. This method can be used to build an inventory of phonemes of a
particular language. This short chain of minimal pairs allows us to determine
that the following are phonemes of English: /p b h ɪ i t d m e/.

It may seem obvious that all these sounds are “meaningful,” but there are many
different ways to pronounce sounds that have no meaningful distinction between
them. Besides all the grunts, burps, squeaks, laughs, etc. that we can make with
our mouths, we have many different types of sounds we can make that are not
phonemes. For example, pronounce the word “bid” with a long, drawn-out vowel.
We could try to convey this vowel in English spelling as “biiiiiiiid,” or we
could write it in IPA by adding the symbol [ː], which is used to indicate a
lengthened vowel: [bɪːd]. Now let’s contrast them as a minimal pair: [bɪd] and
[bɪːd]. These are two very different ways to say the word, and yet the word
remains “bid.” Therefore, these two vowels fail the minimal pair test, which
tells us that [ɪː] and [ɪ] and not two distinct phonemes in English. They are
simply two non-meaningfully different ways to say the phoneme /ɪ/. These variations
within a phoneme are called allophones, a concept that will
be discussed in more detail later.

One more example of non-meaningful variants within a phoneme will suffice. Again,
take the word “bid,” but this time pronounce the initial consonant with a heavy
breath of air. This is an “aspirated” [b], (from the word “aspiration” which means
breathing). We can signify it in IPA by adding a superscript h like this:
[b^h]. If we contrast “bid” said in the usual way with the word with
an aspirated b: [bɪd] and [b^hɪd], we find that the pair do not create
two distinct words and therefore the sounds fail the minimal pair test. Therefore
there is no contrastive difference between [b] and [b^h] and they are
not two distinct phonemes. Instead, they are simply two allophones of the
phoneme /b/.

Every language has its own set of phonemes.
There are languages in which the length of a vowel changes the meaning of a word.
This was the case in English 1000 years ago, when the word “ac” with a short vowel
[ɑk] meant “but” and the word “ac” with a long vowel [ɑ:k] meant “oak tree.” Thus,
in Old English /ɑ/ and /ɑ:/ were two distinct phonemes, whereas now in Modern
English they are two allophones of the same phoneme /ɑ/. Similarly, there are
languages like Hindi in which /b/ and /b^h/ are two distinct phonemes. The
number of phonemes in different languages can also vary widely. Humans have the
ability to produce about 600 different consonant sounds and 200 vowel sounds,
but English only uses about 24 consonant phonemes and 15 vowel phonemes, for a
total of 39 distinct meaningful sounds.
Ubykh,
an extinct language from the Caucasus, had 86 phonemes–84 consonants and only 2
vowels! Hawaiian,
on the other hand, has only 13 distinct phonemes, 8 consonants and 5 vowels. It
does not matter how many phonemes a language has; what matters is that the set of
phonemes function as a system, where those sounds and only those are meaningful and
capable of carrying information. (If you are interested in how babies begin to
distinguish the phonemes of their own language, see
“Does an 11-week-old
know what English sounds like,” from which the figures above on the total
number of consonant and
vowel sounds humans can make were taken).