If you’re interested in language, chances are you’ve wondered about things like how we put bits of language –sounds, meanings and words– together to create some larger expression of communicative meaning. In other words, you’ve probably wondered at some point about how to make a sentence. If you’re been particularly keen and tried to read up about how linguists examine sentences, you’ve probably come across a bunch of funny-looking, often intimidating diagrams known as ‘syntax trees’. Unsurprisingly, many people are put off by the perceived complexity of a syntax tree, and are thus unable to go much further in their quest to understand how we make sentences. This post aims to resolve this problem by showing you the basics of how to grow your own syntax tree.

Why would I want to grow my own syntax tree?

Trees are important because they help us to understand how (and perhaps even why) we put linguistic items together when creating a sentence, since the pattern underlying a sentence isn’t necessarily the same as what we see on the surface. For example, Groucho Marx’s famous line ‘I shot an elephant in my pyjamas’ is dependent on two different syntactic structures for the humorous double meaning, enabling the one-liner ‘and how he got into my pyjamas I’ll never know’. If you can ‘grow’ your own sentence tree, you’ll be able to map out the patterns, and therefore uncover the underlying differences in these structures, for yourself.

Sowing the seeds: the basics

A syntax ‘tree’

Before we start, it’s worth remembering that the theory behind growing a syntax tree is still a work in progress; although linguists tend to agree on some fundamentals, there’s not necessarily a right or a wrong way of sowing the seeds and pruning the tree. Here, our basic syntax tree has the following: a verb-based “root”, a tense “trunk” and a sentence “crown”.

Our tree is anchored by its roots: the verb from which the rest of the sentence grows. A verbal ‘root’ (“VP”; ‘P’ stands for ‘phrase’) in English could be: grow, inspect, calculate, shake, wriggle.

Of course, we can’t have a tree without a trunk: likewise, we can’t have a verb unless it is appropriately modified to illustrate tense (or similar inflection). To illustrate tense (“TP”), we might need to modify a verb to show that is an infinitive, e.g. to grow, to inspect; or a present, past or future tense: (he) shakes, calculated, will wriggle.

Tree Structure
Tree Structure template

Finally, just as a crown tops off a tree, in a syntax tree, the ‘crown’ (“CP”) tops off the structure and tells us (amongst other things) what type of sentence we’re dealing with. Question words (e.g. ‘how many?’) and subordinators (e.g. ‘that’, ‘if’) go here, indicating ‘interrogative’ and ‘embedded sentence’ respectively. For the basic trees we’re growing here, we don’t need a CP, but in a real-life sentential forest, you’d of course want to sow sentential seeds that will grow into different types of sentences.

From seeds to sapling: your first syntax tree

All units are grouped together in twos, and are represented by a binary ‘branch’ (a triangle without the bottom line) in the tree. The more our sentence grows, the more the branches on our tree grow.

'Tense' and 'Verb' slots filled in
‘Tense’ and ‘Verb’ slots filled in

The three-level structure CP-TP-VP gives us our core sentence (or ‘tree’) template, but you’ve probably noticed there’s something missing: the ‘actors’ that take part in the ‘scene’ described by the verb, e.g. she will eat a cake. Now, in the surface structure, she is higher than the tense (will) and the verb (eat), but, as you might agree, the participants are a pretty crucial part of the sentence. A participant doesn’t denote sentence type (CP) or tense (TP). Instead, sentence participants are involved in telling us who does what to whom.

We already know that the ‘doing what’ is illustrated by the verb (i.e. ‘doing’ is the action, and ‘what’ is the actual meaning of a verb), anchoring the ‘root’ of our sentence. It stands to reason that the who and to whom also anchor the sentence within its ‘roots’. Indeed, there is a lot of cross-linguistic evidence for this, but all we need to know for now in order to grow our tree is that the participants – the subject (the “who”) and the object (the “(to) whom”) – originate at the roots of our tree, too.

Since all units are grouped together in twos, we next need to work out what groups together with what: in a sentence like ‘she will eat a cake’, the verb can only group first with either the subject (‘she’) or the object (‘a cake’). This initial grouping can then group with whatever’s left over, to form a larger unit. To work out what groups with what, we can ask the following questions:

Question: What will she do?

Answer: Eat a cake. ✓


Question: What will happen to the cake?

Answer: She will eat.  

Answer: She will eat it. ✓

From the above questions, we can tell that ‘eat a cake’ (i.e. verb + object) form a complete group, whereas ‘she will eat’ (i.e. subject + verb) do not. We need to substitute in ‘it’ to complete the latter phrase, i.e. we need to put an object in to make it work. This suggests that the verb + object combination is our first grouping because it can stand alone (subject + verb cannot). The subject + (verb + object) combination must be our second grouping. Indeed, ‘she will eat a cake’ can stand alone as a functioning phrase, as exemplified by the following question:

Question: what will happen?

Answer: She will eat a cake.  ✓

Our sentence’s root structure must look like this:

Of course, ‘she’ is now in the wrong place for the sentence we are growing (note that we have grown a simple question though!). We must therefore look for somewhere where ‘she’ can move to in order for the sentence to make sense. There is only one slot remaining: just above ‘will’. And that gives us the correct surface order:

'She' moves from its origin in the VP to above the tense slot ('will'), in order to grow the correct surface structure

And there you have it. We have grown a syntax tree! Why not have a go and see if you can grow your own simple sentences? Here are some you might like to try:

  • He will dance the tango.
  • She would play a game.
  • We have read a book.
  • She shall have music.
  • You have met my mother.
  • Groucho had shot an elephant.