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Sentence stress (/ˈsen.təns stres/)


If you have not followed the guide to word stress, now might be a good time.
To analyse sentence stress (and intonation) we need to speak of tone units (or tone groups or intonation contours, depending whom you read).


The tone or sense unit

On this site, we'll use the term tone unit and, following Crystal, we'll divide it into a pre-head, a head, the nucleus and a tail.  In a sentence such as I went to London last week, normally pronounced with no special emphasis, we have:

The reason that LONdon is spelled the way it is is to show what is called the tonic syllable which is the most prominent (i.e., longest, loudest and highest pitched) in the tone unit.

The utterance doesn't have to be pronounced that way.  If it is said in answer to the question
    When did you go to London?
the tone units might change to move the nucleus to last WEEK because that is now the key information.

Tone units are discussed in slightly more detail in the guide to intonation because it is in the study of intonation that they play a crucial role.

If you are not familiar with phonemic transcription, do not worry now.  In what follows, we will be using very little.
There is a course in learning to transcribe English sounds phonemically on this site.



A distinction is often averred between languages which are syllable timed and those, like English, which are stress timed.  There are two fundamental forms of stressing.
The following is the theory.

  1. Syllable timing
    1. In some languages, such as French, Italian, Spanish, Cantonese and Mandarin, every syllable is perceived as taking up the same amount of time.  This is the so-called 'machine gun' sound of these languages.  So we get:
      I ... went ... to ... Lon ... don ... with ... my ... bro ..ther
    2. The length of time it takes to say a sentence in syllable-timed languages is dependent on the number of syllables it contains, therefore.
    3. Vowels in syllable timed languages maintain their essential identity (although they may be shortened in rapid speech).
  2. Stress timing
    1. In other languages, notably English, Dutch, Persian languages, Russian, many Arabic varieties and Scandinavian languages, some syllables take longer to say than others and this results in a reduction of the syllables in between.  So we get
      Iwentto ... L o n d'n ... withmy ... b r o the(r)
    2. In stress-timed languages, by contrast, the length of time it takes to say a sentence depends on the number of stresses it contains, not the number of syllables.
    3. So that the stresses fall evenly, speakers are obliged to weaken and shorten the vowels in unstressed syllables and that leads to the reduction of to from /tuː/ (pronounced the same as two or too) to /tə/ or even /t/ and the reduction of all the other vowels in the unstressed syllables so it sounds like Iwentlondnwimbrotha.  That could be transcribed as /ə wentə ˈlʌn.dən wɪ mə ˈbrʌð.ə/.
    4. The upshot is that vowels in unstressed syllables lose their quality and, in particular, long vowels get shortened:
          /iː/ (as in been) gets shortened to /ɪ/ (as in bin)
          /uː/ (as in goose) gets shortened to /ʊ/ (as in put)
          /ɜː/ (as in nurse) gets shortened to /ə/ (as in about) and so do other vowels
          /ɑː/ (as in heart) gets shortened to /ɒ/ (as in hot)
      and a number of consonants such as /t/ and /h/ may be omitted altogether.
    5. Languages which exhibit the phenomenon of stress rather than syllable timing are known as isochronous.
    6. Click here for a list of commonly weakened words in connected speech.  You will see that they are almost all grammar or function words rather than carrying meaning content.

However, even if this distinction exists, it is not an either-or one.  Languages will vary along a cline from syllable- to stress-timing tendencies.
(There is, in fact, a third form of timing: Mora timing.  In Japanese, e.g., a vowel (V) takes the same time to utter as a consonant (C) plus a vowel so V takes the same time as CV and CVV takes twice as long as CV.  Slovak is often considered also to be a Mora-timed language.)

Here's a rough guide to which languages tend to be more or less syllable- or stress-timed:



ARABIC (with variations)
JAPANESE (also Mora timed)
THAI (also tonal)
VIETNAMESE (also tonal)

In the real world, it has not been possible to measure an appreciable difference in the length of syllables across languages which would support the division above and it is suggested that the differences are not to do with timing so much as to phenomena such as vowel reduction which are the cause, not the effect, of perceived differences in rhythm.
It has further been suggested that all languages exhibit both types of stressing to various extents.
It has also been claimed that different dialects of the same language will vary in this respect.

This is not to say that the concepts of timing and patterns of stress are useless in the classroom but they do need to be handled with care.  Alerting learners to the features of connected speech in English, in particular, vowel reduction in unstressed syllables and the pitch movements which occur in stressed syllables, is important both for comprehension and production.

As was explained in the guide to word stress, three things change when we stress a syllable:

  1. Loudness: how much force is used when saying the syllable
  2. Pitch: stressed syllables are often pronounced in a higher tone
  3. Length: stressed syllables take longer to utter than unstressed ones


Focusing on new rather than given

There is a strong tendency in English to present new information towards the end of any utterance, a phenomenon sometimes called end focus.  Take for example:

In this exchange, it is a fairly easy matter to suggest that the nucleus of the answering response will be SHIRT because this answers the question.  We will have, therefore:

However, if the response is:

Then we probably have two tone units:

The reason is that it is clear to both speakers that they know the person in question and very probably also know that she bought something.  The only new information is, therefore, presented at the end of each tone unit and takes the tonic stress.


New information, not shared by both speakers determines where the tonic stress will fall in each tone unit.

Looked at from a functional grammar point of view, the conventionally stressed item is the last content word of the rheme of the sentence.  So in our example about the shirt, the greatest prominence will be on the adjective awful because that is the last content (not function) word in the sentence.
The theme of the sentence is She bought a shirt and the rheme is what follows.  What this means, in effect, is that the adjective, awful, will form the topic of the next sentence which might be something like:
    What was wrong with it?

Here is another example from the guide to intonation:
    Because she wanted to meet his mother, she travelled up to London
the greatest pitch movement (a rise-fall) occurs on the final part of the rheme, London.
If we reverse the clauses, the pitch movement stays in the same place but, of course, it will now fall on mother because that is now the last content word in the rheme of the sentence.  It looks like this:
So, reversing the clauses in a complex sentence like this involves making sure that the stress remains where it belongs.  Raising one clause or the other to the theme position also has communicative implications, of course.


The conventionally stressed item will be the last content word in the rheme of the sentence.

There is a little more on this in the guide to theme-rheme structures (new tab).


Showing stress and tone movement

In the classroom, it is necessary to develop and use consistently some means of showing where the stress falls and how the tone is changing on the tonic syllable.  Each time a model sentence is presented, for whatever purpose, it is helpful to learners if there is some graphical way of drawing their attention to the sentence stress pattern.
In the guide to word stress, three obvious choices were presented:

highlight highlight highlight

The same can be done with sentence stress with the addition of an arrow to show the tone movement.  Like this:

sentence stress


Special or contrastive stress

We do not, unless we are praying or talking to ourselves, speak in isolation.  We continually get, and sometimes suffer from, feedback from whomever we are engaged with in conversation.  Take this example:

It's probable that the sentence stress will fall like this:

Which obeys all the rules concerning the stressing of new information and its placement.

However, if the conversation takes a different turn, things may alter to allow for the other speaker's feedback:

In this, the speakers apply special stress in order to respond to the other speaker's emphasis, error or misunderstanding.
Everyone does that, in all languages, so it will not be mysterious to your learners.
It is, however, important that we present the 'normal', i.e., canonical word stress to our learners before focusing on special stress in sentences or we run the risk of confusing them.  If you do feel the need to practise special stress, it can be done by taking a simple statement and varying the question.  Like this:

and so on.
Notice, however, that as the exercise goes on, the responses become ever more unnatural because the word order does not change and the tail of the tone unit gets ever longer.  To comply with end focus (and to keep the theme-rheme structure conventional), most speakers will rephrase to get something like:
    At the party in London he spoke to ME
    At the party in London I was spoken to by HIM
Even with special or contrastive stress, end focus will often rule the roost.

Special stress may also cancel out normal word stress so we might find something like:



There is a guide to constituents of phrases (new tab) on this site.  The following comes from the guide to post-modification of noun phrases (new tab) where similar considerations apply.

We need to be slightly careful in deciding what exactly a prepositional phrase is modifying or our hearers can misinterpret what we mean.
For example, the sentence:
    Jane spoke to the man behind the bar
can be understood in two ways, like this:
In the first sentence, the verb is being post-modified and tells us where she spoke so the separated verb phrase is:
    spoke ... behind the bar
Strictly speaking, we have a verb phrase and a prepositional phrase modifier here rather than a pure verb phrase.  A verb phrase, technically, can only contain verb forms so the verb phrase is spoke and all else is modification of it.
In the second sentence, the noun is being post-modified and the object noun phrase is:
    the man behind the bar
When the first sense is intended, speakers will insert a slight pause between the man and behind the bar, making two tone units each with a stressed syllable: the man and behind the bar.

We get, therefore, two possible tone-unit divisions like this:
    Jane spoke to || the man || behind the bar
    Jane spoke to
|| the man behind the bar



One obvious function of special stress and the deliberate moving of the tonic syllable is to disambiguate what might otherwise be unclear.  For example, the sentence:

Anastasia hit the man with the chair

has two possible interpretations if no context or co-text is available:

  1. The man had a chair and Anastasia hit him
  2. What Anastasia hit the man with was a chair

The only way a hearer can figure out what is meant is by paying attention to how the utterance is stressed:

1 Anastasia hit the MAN with a chair
pre-head head nucleus tail
2 Anastasia hit the man with a CHAIR
pre-head head nucleus -

Saying both of these aloud makes it clearer.  Notice, too, how the timing nature of English forces you to compress the unstressed syllables.

This is the index of other guides in the in-service pronunciation section.
the overview of pronunciation connected speech consonants
intonation minimal pairs (PDF) minimal pairs transcription test
sentence stress syllables and phonotactics teach yourself transcription
teaching pronunciation IP teaching troublesome sounds verb and noun inflexions IP
vowels word stress identifying word-stress IP
Guides marked IP are in the initial plus section.

Crystal, D, 2008, A Dictionary of Linguistics and Phonetics (6th edition), Oxford: Blackwell Publishing
Kelly, G, 2000, How to Teach Pronunciation, Harlow: Longman