How to Limit Syntactic Ambiguity in Plain English

Written by Lauren Carter | Last updated:

A few weeks ago I read a heading for a short course. It read “Reducing Racism and Human Rights Course”. My linguistic brain immediately had a chuckle — was it a course for reducing racism and also reducing human rights? My logical brain knew otherwise, but it’s interesting that my brain immediately interpreted that meaning. Let’s dive into why my brain interpreted it like this and how to minimise this problem in your own communication.

What is syntax?

The reason I interpreted that heading in the way I did is because of something called syntactic ambiguity. To understand this, we need to first understand what syntax means.

Although it might sound like a really fancy word (and maybe it is!), syntax just means sentence structure. If you ever hear someone say “the syntax is very difficult”, they just mean “the way the sentence is formed is very difficult”. Here’s an example of two different syntactic structures:

  • Jonathon hit the ball.
  • The ball was hit by Jonathon.

While both of these examples include exactly the same main words, they have slightly different uses. The first example is in the active voice and emphasises Jonathon. The second example is in the passive voice and emphasises the ball. Active and passive sentences are just two different syntactic structures we can use in English.

So basically, syntax just means sentence structure or the way the sentence is formed. The two examples above are very straightforward examples because the sentences aren’t long, nor are the phrases within the sentences.

What is syntactic ambiguity?

For those who don’t know, syntactic is the adjective form of the noun syntax. When we refer to syntactic ambiguity, we just mean that there is more than one way to interpret the sentence’s meaning (or a part of the sentence) and that the reason for that is because of the sentence’s structure. When we think about a sentence’s structure, or its syntax, we can use square brackets to show which parts belong to each other. Here are some examples:

  • [Jonathon} [hit] [the ball].
  • [The ball] [was hit] [by Jonathon].
  • [The man with the bird tattoos all over his arm] [has] [a really nice beard].

We can further segment the last example like this to show exactly how the subject is made up syntactically:

  • [The man [with the bird tattoos all over his arm] ]

And again like this:

  • [The man [with the bird tattoos [all over his arm] ] ]

So, in this example it’s clear that we’re talking about a man with lots of bird tattoos on his arm . . . or is it?!? ? I could use exactly the same words and order but have a different meaning. Let me explain.

If I say “The man with the bird tattoos all over his arm has a really nice beard”, I’m definitely talking about a male who has tattoos of birds on his arm and also happens to have a really lovely beard. The syntactic breakdown is like this:

  • [The man [with the bird tattoos [all over his arm] ] ] [has] [a really nice beard].

BUT, I could also say this “The man with the bird tattoos all over his arm every Sunday morning”. At first when you read this sentence, you might think it’s incorrect, but it’s completely grammatical (albeit very odd!). Let me show you why. Here’s the syntactic breakdown:

  • [The man [with the bird] ] [tattoos] [all over his arm] [every Sunday morning].

In this example, there’s a man who has a bird and he is tattooing all over his own arm (or another male’s arm), and he does this every Sunday.

But how can the words and structure be the same but the meaning be so different I hear you ask? It’s actually a really simple explanation.

How does syntactic ambiguity occur?

While there are many reasons why syntactic ambiguity occurs, I find that it often occurs because of one thing: word classes. If you’re not familiar with word classes, it just means a category of words that have similar grammatical characteristics. Sometimes they’re also called parts of speech. Nouns, verbs, adjectives, adverbs, pronouns, and prepositions are all word classes or parts of speech.

When syntactic ambiguity occurs, it’s usually because some words can belong to multiple word classes. Like in the examples above, the word tattoo can be a noun or a verb. You can say “she has two tattoos on her back”, which is using tattoos as a noun (like in the first example above). But, you could also say “she tattoos ten people every day”, which is using tattoos as a verb (like in the second example above). This ambiguity happens most often with words that can act as nouns and verbs. Other examples of words like this are demand, hand, and smile.

Another common way that syntactic ambiguity occurs is when we use words to modify other words in lists or when using “and”. Let’s take the example that spurred this whole post: Reducing Racism and Human Rights Course. You could interpret this as having two meanings and syntactic structures:

  • [ [Reducing Racism] [and] [Human Rights] ] [Course]
  • [Reducing [Racism and Human Rights] ] [Course]

The first meaning is that the course is about human rights and reducing racism. The second meaning is that the course is about reducing human rights and reducing racism. It’s a very subtle difference from a linguistic perspective, but the implications are huge from a semantic point of view. (Semantic just means “meaning” if you didn’t know.) This ambiguity occurred because it was unclear whether “reducing” was just modifying “racism” or also modifying “human rights”.

Different types of syntactic ambiguity

There are two types of syntactic ambiguity: global ambiguity and local ambiguity. Global ambiguity is when a sentence has more than one interpretation and it’s not clear which one it is when you finish reading it. Local ambiguity, on the other hand, is when a sentence is ambiguous as you read it, but by the time you finish reading or when you re-read it, it actually only has one interpretation.

“Reduce Racism and Human Rights Course” is an example of global ambiguity (even though it’s pretty clear what the intended meaning is, can we REALLY be sure of that? ?). “The man with the bird tattoos all over his arm every Sunday morning” is an example of local ambiguity.

We need to be mindful of global ambiguity because sentences with this ambiguity don’t have a clear meaning. Sometimes from the context we might know what the meaning is most likely to be, but it’s not 100% clear what the meaning actually is.

How can I limit syntactic ambiguity in my own communication?

As I always say, the first step to communicating clearly is to first simply notice. Notice how you write or say things. Notice how others communicate. Be aware and on the look out for ambiguity. I assure you — once you’re looking for ambiguity you’ll notice it more often than you thought you would!

Once you’ve noticed it, then you’ll want to change it so you can make your communication clearer. Every situation is different, so you’ll need to be creative with how you remove the ambiguous parts of the sentence, but here are some tips:

  • Be clear which words should be modifying certain words and which shouldn’t. For example, add an extra verb (“reducing racism and increasing human rights course”)
  • Move words or phrases around in the sentence. For example, move a phrase without a verb to the front so it’s clear that the verb isn’t modifying that phrase (“human rights and reducing racism course”)
  • Completely re-write the sentence. For example, change one sentence into two (“the man has a bird, and he tattoos all over his arm every Sunday”)

Of course, this isn’t an exhaustive list, but it will give you a starting point.

This week’s challenge

So, this week I urge you to continue being curious about language and notice when ambiguity occurs. This could be in your own language or someone else’s. Once you’ve identified it, use the steps above to make it clearer and remove the ambiguous parts. This may be hard at first, but with practice it will become second nature to you.