Sentence Stress  

Sentence stress (also called prosodic stress) refers to the emphasis placed on certain words within a sentence. This varying emphasis gives English a cadence, resulting in a natural songlike quality when spoken fluently.

Sentence stress is generally determined by whether a word is considered a “content word” or a “function word,” and the vocal space between stressed words creates the rhythm of a sentence.

In the most basic pattern, content words will always be stressed, while function words will often be unstressed. Let’s briefly discuss the difference between the two.

A content word (also known as a lexical word) is a word that communicates a distinct lexical meaning within a particular context—that is, it expresses the specific content of what we’re talking about at a given time. Nouns (e.g., dog, Betty, happiness, luggage), most* verbs (e.g., run, talk, decide, entice), adjectives (e.g., sad, outrageous, good, easy), and adverbs (e.g., slowly, beautifully, never) all have meaning that is considered lexically important.

Content words will always have at least one syllable that is emphasized in a sentence, so if a content word only has a single syllable, it will always be stressed.

(*Auxiliary verbs are specific types of verbs that are used in the grammatical construction of tense and aspect or to express modality—that is, asserting or denying possibility, likelihood, ability, permission, obligation, or future intention. These types of verbs are fixed in their structure and are used to convey a relationship between other “main” verbs, so they are considered function words, which we’ll look at next.)

A function word (also known as a structure word) is a word that primarily serves to complete the syntax and grammatical nuance of a sentence. These include pronouns (e.g., he, she, it, they), prepositions (e.g., to, in, on, under), conjunctions (e.g., and, but, if, or), articles (e.g., a, an, the), other determiners (e.g., this, each, those), and interjections (e.g., ah, grr, hello).

In addition to these parts of speech, function words also include a specific subset of verbs known as auxiliary verbs, which add structural and grammatical meaning to other main verbs. These include the three primary auxiliary verbs be, do, and have, as well as a number of others known as modal auxiliary verbs, such as can, may, must, will, and others.

Finally, function words, especially those with only one syllable, are commonly (but not always) unstressed in a sentence—since they are not providing lexical meaning integral to the sentence, we often “skip over” them vocally. For example, in the sentence, “Bobby wants to walk to the playground,” the particle to, the preposition to, and the definite article the are all said without (or without much) stress. The content words (Bobby, wants, walk, and playground), on the other hand, each receive more emphasis to help them stand out and underline their importance to the meaning of the sentence.

While function words are often unstressed in a sentence, those that have more than one syllable still have internal word stress on one of their syllables. For example, the word because has two syllables (be·cause), with stress placed on the second syllable (/bɪˈkɔz/). However, in a sentence with a normal stress pattern, because will have less overall emphasis than the content words around it, which helps maintain the cadence and flow of the sentence in everyday speech.

Likewise, multi-syllable content words will have even more emphasis placed on the syllable that receives the primary stress. It is this syllable that is most articulated within a sentence, with the rest of the word being unstressed like the function words.

Let’s look at some examples, with function words in italics and the primary stress of content words in bold:

(*Note that be is technically a content word here—it is the main verb in the phrase will be late—but it remains unstressed like a function word. Because they are often used as auxiliary verbs to form verb tense, conjugations of be are almost always unstressed in sentences irrespective of their technical grammatical function.)

English is what��s known as a stress-timed language, which means that we leave approximately the same amount of time between stressed syllables in a sentence to create a natural cadence. These are sometimes referred to as the “beats” of a sentence.

This rhythm is easier to hear in sentences in which content words and function words alternate regularly, as in:

Things become more complicated when a sentence has multiple content or function words in a row.

Generally speaking, when multiple function words appear together, we vocally condense them into a single beat, meaning that they are spoken slightly faster than content words on either side.

When multiple single-syllable content words appear together, the reverse effect occurs: a greater pause is given between each word to create natural beats while still maintaining the proper amount of emphasis. (Content words with more than one syllable are usually not affected, since at least one part of the word is unstressed.)

Let’s look at one of our previous examples to see this more clearly:

After the first syllable of the content word Jonathan is stressed, the words will be and the last two syllables of Jonathan are all unstressed and spoken together quickly to form a beat before the next content word, late. The next two words, because his, are also unstressed and spoken quickly to form the next beat. The next three words, car broke down, are all content words, and they are each stressed separately. Because of this, we add a slight pause between them to help the rhythm of the sentence sound natural.

This rhythmic pattern between stressed and unstressed words occurs when a sentence is spoken “neutrally”—that is, without any additional emphasis added by the speaker. However, we can add extra stress to any word in a sentence in order to achieve a particular meaning. This is known as emphatic stress.

The convention regarding the stress and rhythm of content words and function words is consistent in normal (sometimes called “neutral”) sentence stress. However, English speakers often place additional emphasis on a specific word or words to provide clarity, emphasis, or contrast; doing so lets the listener know more information than the words can provide on their own. Consider the following “neutral” sentence, with no stress highlighted at all:

Now let’s look at the same sentence with emphatic stress applied to different words, and we’ll see how its implied meaning changes accordingly:

In writing, we normally use the italic, underline, or bold typesets to represent this emphasis visually. Italics is more common in printed text, while underlining is more common in handwritten text.

Another quick way to indicate emphatic stress in writing is to put the emphasized word or words in capital letters, as in:

This is much less formal, however, and is only appropriate in conversational writing.