April 5, 1999

Some events are inherently iterative, such as tapping or scratching; but we can modify it to mean just one tap if necessary. So the verbs 'tap' or 'scratch' have inherent iterative meaning. Other verbs have properties of completion. For instance, 'he has walked to the store' means that the action of walking to the store is completed. If we say 'he is walking to the store', he is still in the process of walking. In language, there are grammatical markings which indicate these different aspects of the event frame. For instance, in English, 'have + past participle' indicates the completion of the event and 'be + present participle' indicates the middle of the process of the event.

Events such as 'walk' are usually extended, whereas other events, such as 'arrive' are usually not extended. For the example 'John is arriving', the action is almost completed; the transition is about to happen. There is another sense which is the future, 'John is arriving on Tuesday'. In this case, the action of arriving has a frame which is active and John is involved in that frame. The trip is arranged, so the frame is active and it hasn't been completed, so we can use 'be + present participle' to mean that John is in the middle of the process of the frame, which implies that the point of the frame in which John arrives has not yet occurred and will occur in the future. If there is no trip planned, or if the frame is not active, then 'John is arriving' can't be used. For example, if you are invited to visit a friend two years from now the question 'when are you arriving?' seems very odd.

'John has arrived' indicates that the event has reached the completive state. In another example 'the police have arrived', the frame of arrival of police or rescue workers involves several arrivals; each arrival is punctual, but the successive arrivals occur over time and the 'be + present participle' indicates that the police are in the middle of the process of these successive arrivals. The 'be + present participle' again indicates the middle of a process, but the frame of the situation determines what that process is (successive arrivals rather than one arrival).

Languages often make a distinction between perfective and imperfective aspects. Traditionally, perfective aspect is view as completion; more precisely perfective aspect indicates that an event is being viewed from outside, viewing the event as a whole. The imperfective traditionally indicates non-completion, but it actually means that the event is being viewed from the inside, usually focusing on part of the structure of the event.

Some verbs are inherently imperfective or perfective. 'Jump' is an inherently perfective verb; it usually refers to a single action. 'Walk' is an inherently imperfective verb. If we apply 'be + present participle' to an inherently perfective verb, such as 'he was jumping', there are two possible interpretations. We could understand that the action was iterated, in which case, we are using the structure of iteration and viewing the event as in the process of iteration. Or we can imagine that the person is jumping in slow motion. In this case, there is a different time granularity, which allows us to view 'jump' as a process, which the person is in the middle of. So verbs normally name actions from a particular viewpoint; when other aspects are used with these verbs, other interpretations of the event, such as iteration or different time granularity, arise.

The structure of events is rich enough that language may mark different parts of that structure in their grammatical systems. For instance, Russian has telic verbs in which a complete action can be viewed from its endpoint or from its volitional purpose. These are parts of event structure which Russian can mark morphologically. In English 'he lifted up a glass' is volitional and telic, and 'the building burned up' is non-volitional and telic. These events are viewed from their endpoints, but one is volitional and one is not. You can also focus on the failure to get to an endpoint. For instance, 'he wasn't able to walk to the store'.

Event structure also includes a starting point. 'He started walking to the store.' In this case, you don't know if he got to the store. 'He hasn't started walking to the store.' This sentence negates the start of the walk event, so we know that we has not done any walking. Also, before the starting, there's a readiness point at which you have to have the intention to carry out the action, the right amount of energy, the right posture or position, etc. These are conditions necessary for starting.

So for any action, you have a readiness point, a starting point, a process, which may or may not iterate, and a completion point. You may optionally have a goal or purpose. Actions have this structure; verbs indicate actions with a particular aspect. 'Leave' indicates an action with the perfective aspect; we don't normally think about the process of leaving, we just think about it as a whole action. In sentences, we can use grammar to override the inherent aspect of the verb, as in 'he is leaving, but he hasn't left yet' (he's going through his leaving rituals). All languages have mechanism to change the inherent aspect of verbs.

If you say 'he stopped walking', it means that some walking has been done, that he was in the midst of the process of walking, but that the process was interrupted somehow and he stopped. So the structure of events also includes the possibility that processes can be stopped before they are completed.

In a sentence such as 'I stopped drinking coffee', 'drinking coffee' can have a habitual reading. The notion of habitual activity also has an aspectual structure; you can be in the middle of having a habit or you can stop having the habit. So the process profiled by 'be + present participle' is part of the larger frame of having a habit rather than the more specific frame of drinking coffee. Notice that 'I stopped drinking coffee' can have the sense that I was just in the middle of drinking coffee and I stopped. So the 'be + present participle' can also indicate the process of the specific frame of drinking coffee. A number of frames can be operating in a sentence and the aspect markers may pick out different frames, which is why you can get two reading for 'I stopped drinking coffee'. Therefore, just by looking at the meaning of the verb and the morphology (such as 'be + present participle) will not give the meaning of the whole. The meaning only becomes clear with respect to context and the conceptual frames invoked by the sentence. Further, there can be successive embeddings of frames and their associated aspectual structures, as in 'I started to stop eating sweets.'

Aspect is the structure of events and tense refers to the time. In order to understand the English perfect, as in 'I have left', the time line has to be matched up with event structure. 'I have left' focuses on the completion of the action of leaving. Because the action has to occur before its completion point, 'I have left' also implies that the action occurred in the past. Thus, we get a reading of past time for sentences such as 'I have left'. A phrase such as 'I left' also places the action in the past, but it doesn't focus on the completion of the action.

The Event Structure Metaphor maps onto aspect. When you are in the midst of an event, stretched over time, the event is conceptualized as a container, a bounded region in space, which you can be in the middle of. The metaphors for time are mapped on the time line or moving time. These have to be put together with aspect. Phrases such as 'I'm leaning toward leaving' and 'I pulled back from leaving' came from the metaphor that events are locations, bounded regions in space. Historically, the phrase 'I'm going to leave' was part of the same metaphor, but it uses the infinitive form of the verb rather than the gerund. The verb 'am' indicates the present tense and 'be going to' indicates the process part of the aspect frame. If the process part of the aspect frame is indicated andtied to present time, then the goal of the aspect 'leave' has to come after present time, in other words, in the future. (Just as 'I am walking to the store' indicates that I will reach the store at a future time.) Thus, we can get a future reading out of 'am going to'. Notice that if the aspect of 'be going to' is linked to a past time, the future reading is lost: 'I was going to the store.'

The future formed with 'will' often refers to things which are predicted or are scheduled, as in 'that horse will win the race'. The future present, as in 'The A's play the Yankees tonight', refers to a schedule.

Lexical items are defined within a frame, and each lexical item has semantic roles associated with it. For instance, in 'Joe bought the car for ten thousand dollars from Harry.' For the word 'bought,' its subject is the buyer (Joe) and its direct object is the good (car). The price is expressed in a 'for' phrase; the seller is expressed in a 'from' phrase. So certain verbs have certain syntactic frameworks, and we have to learn which semantic roles in the frame fill the syntactic slots of the verbs. Another example: in 'John paid Harry ten thousand dollar for the car' the buyer is again the subject, but ten thousand dollars is the direct object. The seller is the indirect object and the good is expressed in a 'for' phrase. Syntactic roles are defined by semantic frames. Each verb takes a different perspective on the from. For instance, 'cost' takes the perspective of the buyer. A verb like 'buy' or 'sell' will invoke the commercial event frame, but a verb like 'get' doesn't invoke a frame by itself. The rest of the sentence, however, can invoke a particular frame. For instance, in the sentence 'I got ten thousand dollars for the car,' the verb 'got' doesn't trigger the commercial event frame, but 'ten thousand dollars for the car' does invoke it. This frame system will hook up with the aspect system as well, because the actions involved, such as selling, have aspects.