Blocking
The last type of constraint we mention here is blocking. Blocking involves two expressions, one potential and one actual. We say that a potential expression is prevented from occurring because another expression with the same meaning and function already exists. In the context of inflection, forms like *childs, *oxes, *mouses, and *foots are blocked by the existence of children, oxen, mice, and feet. In fact, wherever we find irregular inflectional morphology, we can say that the irregular forms block the application of the regular, or default, rule. This has been formally articulated in work on Lexical Phonology (Kiparsky 1982) and is related to the Elsewhere Condition, which states that a more specific rule or process applies before a more general rule. The Elsewhere Condition is important in many areas of morphology, not just productivity. For example, we can hypothesize that in the creation of the plural form children from child, the more specific rule, which we can state as “add the suffix [rən] and change the vowel of the root to [ɪ],” applies before the more general pluralization rule, “add /z/.” The application of the more specific rule prevents the more general rule from applying.
We also find blocking of derivational formations. We observed that the existence of the verb mail prevents speakers from using a zero-derived verb *mailbox ‘to put a letter or package in a mail box in order to send it to a recipient’. It would be odd to refer to a piece of silverware that is used to cut food as a cutter because the word knife already exists, unless the new utensil is somehow special. And *corresponder doesn’t occur, presumably because we already have the word correspondent (Barker 1998: 703).
The example cutter is particularly informative, because that word does exist, but in different senses – many of them. There are a number of agentive meanings to the word cutter, used for occupations that involve cutting. Someone who castrates animals is a cutter, as is one who cuts fur or cloth to make garments. We also use the word cutter to refer to someone who edits and cuts motion picture shots and assembles them into a finished sequence, someone who pulverizes ore samples so that they may be subjected to chemical analysis, or someone who cuts gems, monumental or building stones, or glass. There are boats and sleighs called cutters. Incisors (which are distinguished from the teeth called grinders) are called cutters. So are particularly incisive comments. Of particular relevance here is the fact that a number of cutting instruments go by the name cutter, including rotary cutters and the sapphire or diamond point of a stylus.1 The meaning ‘piece of silverware used for cutting’ is conspicuous by its absence. This suggests that true semantic blocking is going on here.
Blocking is an economy principle that can be thought of informally as an injunction to avoid coining synonyms: if you already have a good expression for something, don’t invent another one. Clear evidence that blocking is based on the avoidance of creating synonyms comes from syntax, where it operates just as it does in morphology. Why, for example, do we say this morning, this afternoon, this evening, but not *this night? This expression is blocked by tonight. Remember that blocking does not constrain forming words, but rather forming words with particular meanings, which means that a word may be blocked in one sense but not in another. And indeed, this night is acceptable when it has a different sense from the blocked one, as in the phrase “Why is this night different from all other nights?” where this is used in a more purely demonstrative way. Similarly, while the day before yesterday or the day after tomorrow are both common expressions, we cannot say *the day before today or *the day after today, because we already have the words yesterday and tomorrow with these exact meanings. French, by contrast, has the expression avant hier for the equivalent of the day before yesterday and après demain for the equivalent of the day after tomorrow, so French also blocks the translationally equivalent expression of these phrases, which are perfectly acceptable in English, because we have no word for them. The constraint is thus the same across all languages, but its results depend on the individual existing words of each one.
1 This definition is from the American Heritage Dictionary.
