In the last couple of chapters, we’ve seen lots of ways that sounds can differ from each other: they can vary in voicing, in place and manner of articulation, in pitch or length. Within the mental grammar of each language, some of these variations and meaningful and some are not. Each language organizes these meaningful variations in different ways. Let’s look at some examples.
In the English word please, I could pronounce it with an ordinary voiced [l]: [phliz] it would be a little unnatural but it’s possible. Or, because of perseveratory assimilation, I could devoice that [l] and pronounce it [phl̥iz]. We’ve got two slightly different sounds here: both are alveolar lateral approximants, but one is voiced and one is voiceless. But if I pronounce the word [phliz] or [phl̥iz], it means the same thing. The voicing difference in this environment is not meaningful in English and most people never notice if the [l] is voiced or not.
In the words van and fan, each word begins with a labio-dental fricative. In van, the fricative is voiced and in fan it’s voiceless. In this case, the difference in voicing is meaningful: it leads to an entirely different word, and all fluent speakers notice this difference! Within the mental grammar of English speakers, the difference between voiced and voiceless sounds is meaningful in some environments but not in others.
Here’s another example. I could pronounce the word free with the ordinary high front tense vowel [i]. Or I could make the vowel extra long, freeeee. (Notice that we indicate a long sound with this diacritic [iː] that looks a bit like a colon.) But this difference is not meaningful: In English, both [fri] and [friː] are the same word. In Italian, a length difference is meaningful. The word fato means “fate”. But if I take that alveolar stop and make it long, the word fatto means a “fact”. The difference in the length of the stop makes [fatɔ] and [fatːɔ] two different words. (N.B., In the video there’s an error in how these two words are transcribed; it should be with the [a] vowel, not the [æ] vowel.)
So here’s the pattern that we’re observing. Sounds can vary; they can be different from each other. Some variation is meaningful within the grammar of a given language, and some variation is not.
Until now, we’ve been concentrating on phonetics: how sounds are made and what they sound like. We’re now starting to think about phonology, which looks at how sounds are organized within the mental grammar of each language: which phonetic differences are meaningful, which are predictable, which ones are possible and which ones are impossible within each language. The core principle in phonology is the idea of contrast. Say we have two sounds that are different from each other. If the difference between those two sounds leads to a difference in meaning in a given language, then we say that those two sounds contrast in that language.
So for example, the difference between fan and van is a phonetic difference in voicing. That phonetic difference leads to a substantial difference in meaning in English, so we say that /f/ and /v/ are contrastive in English. And if two sounds are contrastive in a given language, then those two sounds are considered two different phonemes in that language.
So here’s a new term in linguistics. What is a phoneme? A phoneme is something that exists in your mind. It’s a mental category, into which your mind groups sounds that are phonetically similar and gives them all the same label. That mental category contains memories of every time you’ve heard a given sound and labelled it as a member of that category. You could think of a phoneme like a shopping bag in your mind. Every time you hear the segment [f], your mental grammar categorizes it by putting it in bag labelled /f/. /v/ contrasts with /f/ — it’s a different phoneme, so every time you hear that [v], your mind puts it in a different bag, one labelled /v/.
If we look inside that shopping bag, inside the mental category, we might find some phonetic variation. But if the variation is not meaningful, not contrastive, our mental grammar does not treat those different segments as different phonemes. In English, we have a phonemic category for /l/, so whenever we hear the segment [l] we store it in our memory as that phoneme. But voiceless [l̥] is not contrastive: it doesn’t change the meaning of a word, so when we hear voiceless [l̥] we also put it in the same category in our mind. And when we hear a syllabic [l̩], that’s not contrastive either, so we put that in the same category. All of those [l]s are a little different from each other, phonetically, but those phonetic differences are not contrastive because they don’t lead to a change in meaning, so all of those [l]s are members of a single phoneme category in English.
Now, as a linguist, I can tell you that voiceless [f] and voiced [v] are two different phonemes in English, while voiceless [l̥] and voiced [l] are both different members of the same phoneme category in English. But as part of your developing skills in linguistics, you want to be able to figure these things out for yourself. Our question now is, how can we tell if two phonetically different sounds are phonemically contrastive? What evidence would we need? Remember that mental grammar is in the mind — we can’t observe it directly. So what evidence would we want to observe in the language that will allow us to draw conclusions about the mental grammar?
If we observe that a difference between two sounds — a phonetic difference — also leads to a difference in meaning, then we can conclude that the phonetic difference is also a phonemic difference in that language. So our question really is, how do we find differences in meaning?
What we do is look for a minimal pair. We want to find two words that are identical in every way except for the two segments that we’re considering. So the two words are minimally different: the only phonetic difference between them is the difference that we’re interested in. If we can find such a pair, where the minimal phonetic difference leads to a difference in meaning, it’s contrastive, then we can conclude that the phonetic difference between them is a phonemic difference.
We’ve already seen one example of a minimal pair: fan and van are identical in every way except for the first segment. The phonetic difference between [f] and [v] is contrastive; it changes the meaning of the word, so we conclude that /f/ and /v/ are two different phonemes. Can you think of other minimal pairs that give evidence for the phonemic contrast between /f/ and /v/? Take a minute, pause the video, and try to think of some.
Here are some more minimal pairs that I thought of for /f/ and /v/: vine and fine, veal and feel. Minimal pairs don’t have to have the segments that we’re considering at the beginning of the word. Here are some pairs that contrast at the end of the word: have and half, serve and surf. Or the contrast can occur in the middle of the word, like in reviews and refuse. What’s important is that the two words are minimally different: they are the same in all their segments except for the two that we’re considering. And it’s also important to notice that the minimal difference is in the IPA transcription of the word, not in its spelling.
So we’ve got plenty of evidence from all these minimal pairs in English that the phonetic difference between /f/ and /v/ leads to a meaning difference in English, so we can conclude that, in English, /f/ and /v/ are two different phonemes.