3.3 Stress and Suprasegmental Information

So far all the sounds we’ve been considering are segments: the individual speech sounds that we represent with IPA symbols. But when we speak, we also include sounds that are above or beyond the level of the segments. This sound information is called prosody, or suprasegmental information, and it makes up the rhythm, timing, meter, and stress of the words and sentences that we speak. The primary pieces of suprasegmental information are the pitch of sounds, the loudness, and the length.

The pitch of a sound is how high or low it is.  We produce high pitched sounds when our vocal folds have a high-frequency vibration, and when our vocal folds vibrate more slowly, the resulting sound is lower in pitch.

Some languages use pitch information to signal changes in word meaning. If a language uses pitch this way, the pitch information is called tone. These example words are from Yoruba, a language spoken in Nigeria. If you look just at the segmental level, these words all seem to be transcribed the same. But speakers of Yoruba vary their pitch when they speak these words so that the meaning of the word changes depending on whether the second syllable has a high tone, a mid-tone, or a low tone. Probably the best-known tone language is Mandarin, which has five different tones. Looking at these five words, you can see that they contain the same segments, but it’s the tones that distinguish their meaning.

Languages also use pitch in another way, not to change word meaning, but to signal information at the level of the discourse, or to signal a speaker’s emotion or attitude. When pitch is used this way, it’s called intonation rather than tone. English uses pitch for intonation — let’s look at some examples.

Sam got an A in Calculus.
Sam got an A in Calculus!
Sam got an A in Calculus?
Sam? got an A? in Calculus?

All of these sentences contain the same words (and the same segments) but if we vary the intonation, we convey something different about the speaker’s attitude towards the sentence’s meaning. Notice that we sometimes use punctuation in our writing to give some clues about a sentence’s prosody.

Another component of suprasegmental information is the length of sounds. Some sounds are longer than others. Listen carefully to these two words in English. beat, bead. The vowel sound in both words is the high front tense vowel [i]. But in bead, the vowel is a little longer. This is a predictable process in English — vowels get longer when there’s a voiced sound in the coda of the syllable. The diacritic to indicate that a segment is long looks a bit like a colon [iː].

So a sound can change in length as the result of a predictable articulatory process, or, like intonation, length can signal discourse-level information about an utterance. Consider the difference between, That test was easy, and, That test was eeeeeeeeeeeeeaaasyyyyyyyy. Some languages use length contrastively, that is, to change the meaning of a word.  In these words in Yapese, a language of the Western Pacific region, you can see that making a vowel long leads to a completely different word with a new meaning. In these words from Italian, consonant length can change the meaning of a word, so fato means fate, but fatto means fact.

In English, pitch, loudness and length also contribute to the stress pattern in words. English words that are longer than one syllable usually alternate between stressed and unstressed syllables. Stressed syllables are more prominent than unstressed syllable, and what makes them prominent is that they’re louder, longer, and higher in pitch than unstressed syllables. Here are some examples.

The words happy, music, sweater have primary stress on the first syllable, while the words beside, around, descend are stressed on the second syllable. If you’re having a hard time hearing the stress difference, try humming the words to hear the difference in pitch.  Stress on the first syllable sounds like this [humming] and stress on the second syllable sounds like this [humming].

Being able to identify stressed syllables is important when we’re learning to do phonetic transcription, because in English, stressed syllables usually get pronounced with a full vowel, while the vowel in unstressed syllables gets reduced. What does it mean to be reduced? That short mid-central vowel that has the name schwa and the symbol [ə] like an upside-down “e” is the most neutral vowel in English. So the “uh” sound in the first syllable of banana gets transcribed with a schwa because it’s unstressed, but the “uh” in bunny gets a full vowel because it’s in a stressed syllable. We’ll see later in this chapter that stress makes a difference to alveolar stops and to aspirated consonants as well!

To sum up, suprasegmental information, also known as prosody, is that sound information that’s above the level of the segment. It consists of pitch, loudness, and length.  Many languages use prosody to provide discourse-level information, and some languages also use prosody to change word meanings.