The semantics of verbs

Conclusion for chapter I.
If we now consider the first set of verbs, those whose basic form is more naturally the `into/onto' form, then verbs which have one of the following properties alternate: simultaneous forceful contact and motion of a mass against a surface (brush, spread, ...), vertical arrangement on a horizontal surface (heap, pile, stack), force imparted to a mass, causing ballistic motion along a certain trajectory (inject, spray, spatter), etc. Those which do not alternate have for example one of the following properties: a mass is enabled to move via gravity (spill, drip, spill), a flexible object extended in one direction is put around another object (coil, spin, twist, wind), a mass is expelled from inside an entity (emit, expectorate, vomit). As can be seen here, the properties at stake are very precise and their identification is not totally trivial, especially for verbs which can be used in a variety of utterances, with some slight meaning variations.
These properties are derived from the observation of syntactic behaviors. While some properties seem to have a clear ontological status, others seem to be much more difficult to characterize. They seem to be a conglomeration of some form of more basic properties.

CHAPTER II. SEMANTICS OF THE VERB AND SEMANTICS OF THE CONSTRUCTION
A verb, from the Latin verbum meaning word, is a word (part of speech) that in syntax conveys an action (bring, read, walk, run, learn), an occurrence (happen, become), or a state of being (be, exist, stand). In the usual description of English, the basic form, with or without the particle to, is the infinitive. In many languages, verbs are inflected (modified in form) to encode tense, aspect, mood, and voice. A verb may also agree with the person, gender or number of some of its arguments, such as its subject, or object. Verbs have tenses: present, to indicate that an action is being carried out; past, to indicate that an action has been done; future, to indicate that an action will be done. In languages where the verb is inflected, it often agrees with its primary argument (the subject) in person, number or gender. With the exception of the verb to be, English shows distinctive agreements only in the third person singular, present tense form of verbs, which are marked by adding "-s" ( walks) or "-es" (fishes). The rest of the persons are not distinguished in the verb (I walk, you walk, they walk, etc.).Latin and the Romance languages inflect verbs for tense–aspect–mood (abbreviated 'TAM'), and they agree in person and number (but not in gender, as for example in Polish) with the subject. Japanese, like many languages with SOV word order, inflects verbs for tense-aspect-mood, as well as other categories such as negation, but shows absolutely no agreement with the subject - it is a strictly dependent-marking language. On the other hand, Basque, Georgian, and some other languages, have polypersonal agreement: the verb agrees with the subject, the direct object, and even the secondary object if present, a greater degree of head-marking than is found in most European languages.Let us now consider the combination of a verb, with its own semantics, within a syntactic construction. The Construction Grammar approach sheds a particularly clear and insightful light on this interaction; let us present here some of its aspects, relevant to the verb semantic class system. The first point concerns the nature of the verb semantics, the nature of the semantics of a construction and the characterization of the interactions between these two elements. The second point concerns the meaning relations between constructions. These elements are of much importance for lexicalization and the construction of propositions.
Verbs usually have a central use, characterized by a specific syntactic form, but they may also be used with a large variety of other syntactic forms. In this case, the meaning of the proposition may be quite remote from the initial meaning of the verb.
Let us consider a few illustrative cases. In:
Edith baked Mary a cake.
the initial sense of bake becomes somewhat marginal, in favor of a more global meaning:
Edith INTENDS to CAUSE Mary TO HAVE cake'.
There is not here a special sense of bake which is used, but bake describes a kind of `manner' of giving Mary a cake.
Consider now the case of slide, suggested by B. Levin. ¿From the two following sentences:
Edith slid Susan/*the door the present.
Edith slid the present to Susan/to the door.
one may conclude that there are two senses for slide (probably very close). The first sense would constrain the goal to be animate while the second would have no constraint. Now, if we insist, in the ditransitive construction, that the goal must be animate, then we can postulate just one sense for slide, which is intuitively more conceptually appropriate. We then need to posit constraints in the alternations on the nature of the arguments which would then allow only those verbs which meet the constraints to undergo that alternation. As noticed very early by Lakoff, a verb alone (and its associated lexical semantics) cannot be used to determine whether a construction is acceptable, it is necessary to take into account the semantics of the arguments.
Depending on the construction and on the verb, the verb may either play an important part in the elaboration of the semantics of the proposition or may simply express the means, the manner, the circumstances or the result of the action, while the construction describes the `central' meaning. In fact, the meanings of verbs and of constructions often interact in very subtle ways. One might conclude then that there is no longer a clear separation between lexical rules and syntactic rules.
The difficulty is then to identify and describe the syntactically relevant aspects of verb meaning, i.e. those aspects which are relevant for determining the syntactic expression of arguments, via linking rules. Pinker notes that these aspects should exist in small number, since they resemble characteristics of closed-classes. This is not very surprising, since syntactic alternations form a set of closed elements.
Classification of verbs with respect to semantic properties relevant for describing thematic relations
Having dealt with alternations, let's turn to thematic relations and their role in the classification of verbs. Thematic relations express generalizations on the types of lexical functions that are established between the verb and its arguments in the predication. There is a consensus among researchers that assignment of thematic roles to the arguments of the predicate imposes a classification on the verbs of the language. Since the type of thematic roles and their number are determined by the meaning of the verb, the lexical decomposition of verb meanings seems to be a prerequisite for semantic classification of verbs. The close affinity between the compositional and relational lexical meanings plays a central role in the classifications of verbs outlined in this subsection.
This difference highlights the problem of selection of semantic content in NLP lexicons. The following arguments might be posed in favour of the variant which includes the information on a partial semantic representation in the lexicon: (i) significant generalizations about lexical meaning of verbs are accounted for in an explicit way in the verb entry; (ii) such information can support disambiguation of senses in case of polysemy; (iii) as a consequence of (ii), the semantic correctness of verb classifications increases, which in turn can improve the results of syntactic and semantic rules that operate on verb classes; (iv) it can also contribute to the integration of semantic and syntactic content in the lexicon.
There is no doubt that the model of semantic roles from the seventies, and in particular its repertory of roles and definitions, has to be replaced by a more stringent semantic model to suit the needs of NLP. The combination of the Dowty [Dow89] model of protoroles with the model of thematic sorts proposed by Poznansky and Sanfilippo [San92a] and elaborated in Sanfilippo [San93b] seems to be a very interesting proposal or solution (cf. 2.6.2 for description of these models).
Let's finish these general remarks with a quotation from [Lon76], which captures the essentials of verb classification w.r.t. semantic roles. "An understanding of the function of cases or roles is insightful for the understanding of language. Even more insightful, however, is the grouping of these roles with verb types with which they characteristically occur. To do this we must specify features, which distinguish one set of the verbs from another set of verbs, then we must specify the roles that occur with verbs characterised by these features. The result will be sets of verbs with characteristic constellations of accompanying substantives in given role...Such a set of verbs with characteristic accompanying nouns in particular roles is called a case frame. To assemble and compare the case frames of a language is to evolve a semantic typology or classification of its verbs... As soon as one begins to assemble a number of case frames, similarities in sets of case frames begin to be evident. This leads to the feeling that case frames should constitute some sort of system, i.e. that they are not merely list or inventory, but a system with intersecting parameters."