Understanding nuclear stress


This is the first in a pair of posts (read the second post here) on the theory and practice of teaching nuclear stress for English as a Lingua Franca (ELF).

This post aims to answer the following questions:

  1. What is nuclear stress?  What isn’t it?
  2. How is this relevant to ELF pronunciation?

For one reason or another, English language teachers often don’t meet this terminology–let alone fully understand what it means–until they do a higher-level qualification, such as the Cambridge Delta or Trinity DipTESOL.  The principles behind nuclear stress aren’t really all that tricky; the main stumbling block seems to be how much terminology is involved.  But have no fear; all this will be explained below…

Everything you always wanted to know about nuclear stress* (*but were afraid to ask)

Before we get down and dirty with nuclear stress, let’s start by revising some basics.

English words are made up of syllables.   We won’t go into too much depth here about what precisely constitutes a syllable as it’s somewhat besides the point, but if we can agree for the time being that the word “English” has 2 syllables and the phrase “I speak English” has 4, then that should be enough for us to move on.

Some syllables are stressed.  We can probably agree, for example that the first syllable in “English” is stressed.  Producing a stressed syllable requires more muscular energy.  Recognising a stressed syllable requires us to perceive its prominence (we’ll come back to this in more detail later).  This is what we’re asking our learners to do when we put a new word on the board in class, for example, and ask them “Which syllable is stressed?”

So what makes a syllable prominent?  In my experience, trainee teachers are often taught the simple formula: louder, higher, longer.  This seems to me a reasonable simplifcation.  Not everyone finds it easy to identify stress when asked to – usually, they do it naturally without even thinking about it!  So the ‘louder, higher, longer’ mantra helps make this tricky area more tractable.

Pitch is particularly important.  As Roach neatly summaries (2013:203), “if all syllables [in a word] are said with low pitch except for one said with high pitch […] then the  high-pitched syllable will be heard as stressed and the others as unstressed.  To place some movement of pitch (e.g. rising or falling) on a syllable is even more effective in making it sound prominent.”  And, as Roach succinctly puts it, “the word we use for the overall behaviour of the pitch is tone.” (2013:315)

Here’s are two very simple examples of different tones used to change the intended meaning of the same one-syllable utterance:

Example 1:   Yes.   [falling tone, simply answering a yes/no question]

Example 2:  Yes?   [rising tone, answering the telephone/door]

The thing is, one-syllable utterances in English are quite rare.  So what happens when we string words together?  Well, we produce utterances, or “continuous piece[s] of speech beginning and ending with a clear pause” (Roach, 2013:315).

(It’s important to remember at this point that we’re talking about speech and sound. ‘Utterances’  are to do with phonology; ‘sentences’  are to do with grammar).

And when we look at utterances longer than one syllable, we realise that we can only really identify tones (pitch changes) on a few very prominent syllables.

So if we want to analyse the intonation across the whole utterance, we really need to talk about something bigger than a syllable.  For this purpose, linguists talk about tone units.

A tone unit isn’t simple to define, so let’s look at some illustrative examples instead.

Take the word ‘Japanese’.  Three syllables.  The last one is stressed; the first one is also slightly stressed.  So we can say that ‘-ese’ has primary word stress and ‘Jap-‘ has secondary word stress.  These are innate properties of the word, which we see marked in dictionaries with little lines at the top or bottom of the transcription, like this (from the Macmillan online Learner’s Dictionary):


If we simply cite this word (i.e. just say it, like a one-word utterance, as though answering the question “Is she English?”), it forms one complete tone-unit.  The syllable with primary word-stress is most prominent, and we can write it as follows:

// JApanESE //

(The convention in the literature is to represent tone units like this, with double slanted lines showing the boundaries of the utterance, single slanted lines showing the boundaries of tone units, CAPS showing stressed syllables and UNDERLINED CAPS showing prominent syllables.)

In connected speech, however, innately stressed syllables will not necessarily also be prominent.  This is because, unlike word-stress, prominence is not determined by the language itself but by the speaker (Brazil, 1994; Underhill, 1994).  It is possible for prominence not to occur on any of a word’s syllables, despite the stress(es) in its citation (dictionary) form.  For example:

// ACtually she’s japaNESE //

// a JApanese SHIP-owner’s been / KIDnapped //

// i thought SHE was japanese // NOT HIM

(McCarthy, 1991:95)

In these examples, we can see that word-stress and prominence may overlap, but innate word-stress is only automatically placed when a word is quoted as if from the dictionary, whereas in a tone unit, prominence depends on context.

Speakers naturally assign prominence as a matter of course, selecting what information to highlight as the most important part of their message and thereby focusing their listeners’ attention on a particular intended meaning (e.g. she in the last example above, as opposed to he).  Words which carry little information content, or which are predictable or  impossible/improbable to replace with anything different in the current discoursal context are therefore unlikely to be given prominence (e.g. the identity of she in the above utterance ‘Actually, she’s Japanese’ is likely implicitly understood by the speakers.

This brings us (finally!) to nuclear stress, also known as tonic stress.

The most prominent syllable in a tone unit – i.e. the syllable which carries the tonic/nuclear stress, also called the nucleus – is the point at which the major pitch movement happens, and the hearer’s attention is centred around it.

In other words, here’s what it all boils down to:

Placing prominence on a particular syllable draws a listener’s attention to it.  If a speaker places prominence on something he/she DID NOT INTEND to draw attention to, his/her listener is likely to be lost.

Isn’t nuclear stress a particularly native English feature?  Does it really matter in ELF interaction?

It’s true that a great deal of literature on English intonation and stress draws attention to native uses of these pronunciation features.  Some of these sources also imply the common assumption that native speakers of English will be the likely listeners to (and judges of) learners’ pronunciation; for example:

Pennington (1996:253) advocates teachers’ paying attention to stress and intonation as examples of

“general characteristics and overall voice quality which interfere with intelligibility or make the accent sound especially non-native, i.e. non-English or non-standard.”

Underhill (1994:75) also refers to the role of the ‘native listener’:

“What happens when a non-native speaker uses an inappropriate intonation pattern?  My observation is that while within certain limits of intelligibility mistakes or inappropriacies of pronunciation, grammar and even vocabulary can be accommodated by the native listener, inappropriate intonation can at times give rise not just to obscuration of the message, but to reception of a quite different message.”

But in fact, as we will see below, both native and non-native listeners alike can get a “quite different message” due to particular placement of nuclear stress; that is partly why this aspect of intonation features in the Lingua Franca Core.

Moreover, as this blog intends to reflect, many learners today are less likely to be interacting with native English speakers than with other people from different first-language backgrounds.  It is therefore no longer appropriate to assume a native-speaker interlocutor, or to take native-like pronunciation as the only/best goal or model.

Some material for teachers does recognise this state of affairs.  For example, Dalton and Seidlhofer (1994:iv-v) point out that:

“Knowledge about discourse tells us that appropriacy is a more important criterion for intelligibility than correctness.  This view accordingly shifts the emphasis away from native speakers as yardsticks of ‘correctness’ to teachers taking informed decisions as to what is desirable and feasible in order to meet the needs of specific learners.”

David Brazil also explains (1994:1-2), in his excellent coursebook for teaching intonation, that:

“[the book] does not follow the perfectionist tradition, which demands native-speaker-like control of the sounds of a particular accent, and which regards everything else as an ‘error’.  Instead, users are encouraged to see pronunciation from the point of view of how it can best enable them to make their meanings and intentions clear to a listener.”

Our concern on this blog is intelligibility in an ELF context, i.e. “any use of English among speakers of different first languages for whom English is the communicative medium of choice, and often the only option” (Seidlhofer, 2011:7); and Jennifer Jenkins included nuclear stress in her proposals for the Lingua Franca Core (2000), which is, of course, concerned only with intelligibility in ELF.  (Remember that criteria for a particular pronunciation feature’s inclusion in the LFC included whether it appeared likely to hinder intelligibility if used inaccurately and whether it was teachable.  Based on Jenkins’ data and teaching experience, she determined that nuclear stress met both these requirements.)

Let’s consider a brief example from her original data (Jenkins, 2000:50-51) which illustrates the importance of appropriate nuclear stress placement in ELF:

Four students, each from a different L1 background, were engaged in a typical classroom communicative task: creating a poster for the classroom wall.  One student asked the others // have you got a blue VUN//.  The others were lost.  This student was in fact referring to a pen, asking for ‘a blue one’.  When the speaker altered the nuclear stress to say //a BLUE vun//, the others understood; intelligibility was achieved.

In other words, this student had two pronunciation ‘errors’: misplaced nuclear stress and substituting /v/ for /w/ in the word “one”.  In the end, it wasn’t necessary to pronounce the word “one” differently to achieve intelligibility, but simply to place nuclear stress appropriately.  By making the word “blue” prominent, the listener understood the speaker’s intended meaning.

‘Nuclear’ stress, a.k.a…

Different linguists and literature use different terminology.  Sometimes the terms overlap; sometimes they don’t.  Let’s briefly examine some of the main contenders for potential confusion:

  1. Tonic stress – same as nuclear stress.  Confusion over!
  2. Sentence stress – more of a grammatical, rather than phonological, distinction.  The basic idea is that ‘content/lexical words’ (like nouns, adjectives and verbs) will usually be pronounced with greater stress than ‘function/grammatical words’ (like prepositions, articles and conjunctions).  For example, in the question “Do you want to go?” only “want” and “go” will be ‘fully’ pronounced.
  3. Contrastive stress – an example of how the effect of shifting nuclear/tonic stress can be exploited to change meaning by contrasting one word with another that could have been used in its place.  For example, “I love YOU (as opposed to some other guy/girl).
  4. Corrective stress – similar to contrastive stress, and typical of classroom dialogue!  Another example of how the effect of shifting nuclear/tonic stress onto a particular word can be exploited to identify a mistake in something that was said.  For example, “Oops, I meant NEXT month, not THIS month”.  (Aside: In the classroom, this sometimes has the amusing unintended inconsequence of a group of students repeating back to you something you’ve just corrected them on, oddly distorting the standard (citation/dictionary) form of a word.  For example, a student says “The film was really bored.”  You say, “borING!”  The student says, “yeah it was borING.”  You falter and eventually let it pass as they’ll forget the correct adjective ending in a minute anyway.)

How to teach nuclear stress?

See the second post in this series for some practical ideas.


Brazil, D. (1994). Pronunciation for advanced learners of English (Teacher’s book). Cambridge: Cambridge University Press.

Dalton, C. & B. Seidlhofer (1994). Pronunciation.  Oxford: OUP.

Jenkins, J. (2000). The phonology of English as an International Language. Oxford: Oxford University Press.

McCarthy, M. (1991). Discourse analysis for language teachers. Cambridge: CUP.

Pennington, M. C. (1996). Phonology in English Language Teaching. New York: Addison Wesley Longman.

Roach, P. (2013). English phonetics and phonology: A practical course. (enhanced EBook edition). Cambridge: Cambridge University Press.

Seidlhofer, B. (2011). Understanding English as a Lingua Franca. Oxford: Oxford University Press.

Underhill, A. (1994). Sound foundations. Oxford: Macmillan Heinemann English Language Teaching.

Further reading

You might find this online glossary of pronunciation terms useful.  It was compiled by Peter Roach, a prominent phonetician.



10 thoughts on “Understanding nuclear stress

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  9. What a pity the author doesn’t mention my book *English Intonation – an Introduction* (CUP 2006). I think I give a clearer explanation, along with copious examples, exercises, and recordings.

    • Hi John

      Consider it mentioned! If I recall, the author didn’t have your book to hand when compiling this blogpost. It’s the fate of travelling teachers/bloggers, I suppose… access to certain publications is bound to be an issue at times when financial means, membership of specialist libraries or suitcase space is limited.

      Are there any particular points here that you think could be clarified? You’d be welcome to address them in a guest post.


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