Ergative and Unaccusative Verbs

(Download this explanation in PDF here.)

(Before you start this lesson, make sure that you understand transitive and intransitive verbs.)

Usually, when we think about the subject of a verb in English, we think about a person who does the action of the verb. For example, in the sentence 'John ran' or 'Lucy ate the cake', John and Lucy do the eating and running. They decide to run or eat and then they run or eat by themselves. However, sometimes the grammatical subject is not the person who does the verb. We can make sentences like:
  • The door opened.
  • The ice melted.
In both of these sentences, something else (not the subject) caused the action. Maybe a person pushed the door and that made it open. It wasn't the door that decided to open and then opened by itself. In the same way, the ice didn't decide to melt. Something else (the sun, maybe, or a high temperature) caused the ice to melt. This kind of verb is called an ergative verb (or sometimes an 'alternating unaccusative'). They can be confusing, because it's easy to mix them up with the passive. But 'the door opened' and 'the ice melted' are active sentences and the verbs here are intransitive.

'Melt' and 'open' also have a transitive active form (which can make a normal passive form) as well as the intransitive form that I've already talked about. So, we have three possibilities:
  • David opened the door (active, transitive).
  • The door was opened (by David) (passive, transitive).
  • The door opened (active, intransitive, ergative).
It's important to remember that 'the door opened' is grammatically active, not passive. So we can't say 'the door opened by David'. Here are some more examples:
  • The dog broke the vase (active).
  • The vase was broken by the dog (passive).
  • The vase broke (ergative).
  • The pilot landed the plane (active).
  • The plane was landed by the pilot (passive).
  • The plane landed (ergative).
  • The sun is melting the chocolate (active).
  • The chocolate is being melted by the sun (passive).
  • The chocolate is melting (ergative).
There are a few situations when it's natural to choose the ergative form. These include:
  1. When the cause of the action is irrelevant. (The film began.)
  2. When we want to create a feeling of mystery. (The curtains opened and ...)
  3. When the subject is very easily broken or changed, so that it seems like it can change without a person doing anything. (The bubble burst.)
  4. When change usually happens in this case. (In the spring, the snow melted.)
  5. When there are many possible causes for the change. (Wages increased.)
(This list is based on one from 'The Grammar Book' by Celce-Murcia and Larsen-Freeman).

In some cases, it's much more natural to use an ergative than a passive. For example, if you say 'wages were increased' (passive) then we get the idea that somebody decided to increase wages. However, this might not be true. It might be the case that lots of different things (for example, the economy, a lack of skilled workers, demonstrations by trade unions, ...) caused the wages to increase. So, in this case, it's better to say 'wages increased'. However, it's also important to be careful! Not all verbs that talk about change can be used ergatively. For example, we can't use 'demolish', 'destroy' and 'build' like this:
  • The builders demolished the house (active).
  • The house was demolished by the builders (passive).
  • NOT: The house demolished.
  • The child built the tower (active).
  • The tower was built by the child (passive).
  • NOT: The tower built.
Click here for a list of verbs that can be used ergatively.

Non-Alternating Unaccusatives.

As well as ergative verbs, we also have some intransitive verbs that have something that doesn't cause the action as a subject. For example:
  • The accident happened.
This is an active sentence. However, the subject of the sentence doesn't do the action of the verb. The accident didn't decide to happen. Instead, something else caused the accident. These verbs can also be confusing. It's easy to use them in the passive by mistake. But, these verbs are intransitive. They can't make a passive. It's not possible to say 'the accident was happened'.

Verbs like this:
  • Appear: The sun appeared (NOT: the sun was appeared).
  • Arrive: The plane arrived (NOT: the plane was arrived).
  • Die: The plant died (NOT: the plant was died).
  • Disappear: The fog disappeared (NOT: the fog was disappeared).
  • Emerge: A pattern emerged (NOT: a pattern was emerged).
  • Fall: The apple fell (NOT: the apple was fallen).
  • Happen: The events happened (NOT: the events were happened).
  • Occur: The problem occurred (NOT: the problem was occurred).
  • Rise: The bread rose (NOT: the bread was risen).
  • Vanish: The path vanished (NOT: the path was vanished).
Click here for an exercise about ergative and unaccusative verbs.