Semantics and lexicography
Dictionary-writing, or lexicography, is, in the words of Landau (1984: 121), ‘a craft, a way of doing something useful. It is not a theoretical exercise to increase the sum of human knowledge but practical work to put together a book that people can understand.’ Linguistic semantics, by contrast, while also interested in the meanings of words, is exactly the sort of theoretical exercise with which Landau is drawing a contrast. Nevertheless, the model of the dictionary or ‘lexicon’ (an older term for the same thing) has been decisive in the way that many linguists conceive of the nature of language:
Language exists in the form of a sum of impressions deposited in the brain of each member of a community, rather like a dictionary of which identical copies have been distributed to each individual. It is, thus, something that is in each of them, while at the same time common to all and existing independently of the will of any of its possessors. (Saussure 1967: 38)
According to a common assumption, our brains holds a ‘store of words in long term memory from which the grammar constructs phrases and sentences’ (Jackendoff 2002: 130). This stock of words and associated meanings is usually referred to as the mental lexicon. On this view, the primary task of linguistic semantics would be the specification of the stored meaning representation – the ‘entry’ – associated with each lexeme in the mental lexicon:
For the speaker/writer, accessing ‘words’ is a matter of mapping ideas onto those stored meaning representations in the mental lexicon that are associated with stable word forms, which can then be used to implement a spoken or written output. For the listener/reader, the major task is to map portions of the linguistic signal onto the stored neurosensory traces in the mental lexicon; once activated, these will in turn stimulate their associated meaning representations. (Garman 1990: 240–241)
The process of matching a meaning with a word is analogous to that involved in consulting a dictionary. Just as a language-learner discovers the meaning of an unknown word by looking it up in a dictionary, the production and understanding of ordinary speech is conceived of as a process of matching between stored word-forms and the stored meaning representations associated with them in long-term memory. Like dictionary definitions, these meaning representations are imagined as discrete and relatively fixed. And just as dictionaries aim for a maxi mum degree of concision, it has been assumed that the mental lexicon also seeks the most effi cient, least redundant listing of lexemes’ meanings.
In order to serve the purposes of serious linguistic description, the entries in the mental lexicon must be much more detailed than is usual in ordinary dictionaries. As well as containing information about words’ meanings, they must also specify their grammatical properties, and contain a representation of their phonological structure. Consider for example the Concise Oxford Dictionary entry for the verb pour:
v. 1 intr. & tr. (usu. foll. by down, out, over, etc) flow or cause to flow esp. downwards in a stream or shower 2 tr. dispense (a drink, e.g. tea) by pouring. 3 intr. (of rain, or prec. by it as subject) fall heavily. 4 intr. (usu. foll. by in, out, etc.) come or go in profusion or rapid succession (the crowd poured out; letters poured in; poems poured from her fertile mind). 5 tr. discharge or send freely (poured forth arrows). 6 tr. (often foll. by out) utter at length or in a rush (poured out their story).
This entry presents, at first sight, a rather comprehensive description of the verb. But there are a number of aspects of pour’s meaning and use which the definition does not cover. First, constructions like (2) correspond to sense number two, ‘dispense by pouring’, but are intransitive, contrary to the dictionary’s specification.

Furthermore, the dictionary is silent about the conditions under which pour in sense one is ‘usually’ followed by a preposition or prepositional phrase. Whereas (3a) and (3b) are quite acceptable without any following prepositional phrase, (4a) and (4b) seem more questionable, whereas (5a) and (5b) are perfectly acceptable:

Clearly, then, the dictionary’s statement that pour in this sense is ‘usually’ followed by down, out, over etc., needs significant fleshing-out. Similarly, the Concise Oxford does not tell us the limits on the prepositional and subject combinations with which pour is acceptable: why are the (a) examples in (6) and (7) clearly acceptable, but the others less so?

Extended or metaphorical uses of the verb raise a host of similar questions. What is it that determines the acceptability of (8), the unacceptability of (10), and the ‘punning’ quality of (9)?

These and other questions all need to be answered in a comprehensive description of the mental lexicon entry for the verb pour.
QUESTION Can you refine the description of the meaning of pour in order to explain the facts in (2)–(10)? What other aspects of the meaning and use of pour are not made explicit by the quoted definition?