There are other ways of looking at the temporal properties of an event or state than when it occurred or was true. It could be viewed as ongoing or completed, for example. Consider the difference between these two English sentences.

Clark was falling asleep.

Clark had fallen asleep.

Both have an unspecified time in the past as a point of reference. In sentence 3 the event is seen as ongoing at that time, and in sentence 4 the event is seen as completed at that time.

The Speaker may also point out the repeated nature of an event or state. Consider the difference between these English sentences.

Clark runs in the marathon.

Clark is running in the marathon.

For both of these sentences, the point of reference is the utterance time ('now'). In sentence 5, the running is viewed as repeated around this reference time; in sentence 6 it is ongoing at the reference time.

The grammatical representation of duration, completion, and repetition of events and states is known as aspect. As with other grammatical morphology, aspect morphology is often obligatory. In English, for example, speakers have to commit themselves to the choice between ongoing, repeated, or completed for an event with present reference time. That is, it is impossible in English to talk about Clark running the marathon, as in sentences 5 and 6, without making such a commitment.

2.1.2 Possibility, hypothesis, desirability

Another set of properties that distinguishes some events and states from others is related to their truth: whether they are true or likely to be true, whether we are treating them as true just for the sake of argument, whether we would like them to be true. The grammatical represention of meanings like these is called modality. Here are two English examples where the verb morphology reflects these dimensions.

If Jimmy spoke Spanish, he'd have a better chance with Lupe.

Perry suggested that Clark spend less time on computer games.

In sentence 7, the Speaker knows that Jimmy doesn't speak Spanish; if he did or there were at least a possibility that he does, the verb would be speaks rather than spoke. And in the same sentence, would ('d) indicates the conditional nature of the state of «having a better chance»; it would be true if Jimmy spoke Spanish, but he doesn't, so it isn't. In sentence 8, spend is used rather than spends, indicating the tenative nature of the «spending less time»; this is only a suggestion, not yet reality.[2]

2.1.3 Participants

Events and states are defined in part by their participants. The choice of a particular verb commits the Speaker not only to a category of state or event but to a set of semantic roles. But these semantic roles may often be filled by a variety of things. We can group events and states into a small set of abstract categories on the basis of some general properties of these participants. The next subsection focuses on verb morphology with this function.

2.1.4 Verb agreement

What makes the following sentences ungrammatical? What kind of rule can you specify for the verb morpheme – s?

Clark always arrive late.

Clark's colleagues likes him a lot.

In many languages verbs take inflectional morphemes that convey some information about one or more participants in the event or state that the sentence is about. One way to think about this is in terms of the agreement between the verb and those participants on a small number of abstract properties. On the one extreme are languages like Mandarin Chinese and Japanese, which have no morphology of this type (though sometimes the choice of a verb in Japanese is governed by some properties of the participants). In what follows, I'll briefly discuss verb agreement in four languages that have some form of it. Notice that since agreement morphology conveys abstract properties of participants, that is, things, this topic overlaps with the topic of the last section.

English is a language with limited verb agreement morphology, the vestiges of what was a full-blown agreement system in Old English. Consider these sentences.

Clark plays golf.

Lois and Clark play tennis.

I play croquet.

Clark played 18 holes yesterday.

Clark likes team sports.

In English – s is plural when it appears on nouns but singular when it appears on verbs.

Notice that the form of the verb play differs in sentence 9 and 10. In sentence 9 the subject of the sentence, Clark, is 3rd person (that is, including neither the Speaker nor the Hearer) and singular, and the verb takes the suffix – s to indicate this. When the same verb is used with a subject that has any other combination of person and number, as in sentences 10 and 11, the verb takes no suffix. Notice also that an agreement suffix is only added to verbs in the simple present tense, that is, the tense category used in sentences 9, 10, and 11. Sentence 12 is in the simple past tense, and no distinction is made on the basis of person and number. Finally, notice that it is the participant in the syntactic role of subject, rather than any particular semantic role, that the verb agrees with. So in sentence 13, the verb again takes the – s even though the subject in this case refers to an experience rather than an agent, as in sentence 9.[3]

With the verb be, there are three forms rather than two in the simple present, and rather than suffixes, completely unrelated forms are used: am (1st person singular), is (3rd person singular), and are (other person-number combinations). The verb be also has two forms in the simple past tense, was and were.

Thus English subject-verb agreement is limited both in terms of the number of different forms and the situations in which it must apply. However, it behaves just like the other examples of grammatical morphology we've been considering. It is often redundant, but it is obligatory even when it is. So in standard English dialects, at least, it is ungrammatical to say Clark like Lois, even though the missing – s would convey no new information.

So does the – s in play in sentences 9 and 13 mean anything? Yes, it means that the subject of that verb is 3rd person singular. In addition, because this suffix only occurs on verbs in the simple present tense, it also marks that tense category. Under most circumstances, this information would be obvious from the subject itself and from the context. But if the Hearer missed the subject for some reason, that – s could help sort things out. Also there are gray areas where Speakers may choose to use a verb in the 3rd person singular with a plural subject. Compare these two sentences.