Corpus linguistics and a dictionary-based jurisprudence

(Daniel White/Daily Herald via Associated Press)

We're talking this week about the application of corpus linguistics to questions of legal interpretation and the search for the ordinary meaning of the words in a statute. Before diving into the corpus tools that can be brought to bear on this question, it is worth highlighting one of the existing (and increasingly common) approaches to finding ordinary meaning—the citation of general-use, unabridged English dictionaries.

The increasing reliance on dictionaries in legal interpretation has been well documented (here, here and here). But dictionaries cannot tell us the "ordinary meaning" of words in their statutory context. This is not a failing of dictionaries or the lexicographers engaged in the harmless drudgery of creating them. As Professors Henry Hart and Albert Sacks observed in their influential "Legal Process" lectures:

A dictionary, it is vital to observe, never says what meaning a word must bear in a particular context. Nor does it ever purport to say this. An unabridged dictionary is simply an historical record, not necessarily all-inclusive, of the meanings which words in fact have borne …

We see the problems of a dictionary-based approach to ordinary meaning play out in a number of cases. For example, in Muscarello v. United States, the Supreme Court was called upon to determine whether a statute that imposes a mandatory five-year sentence enhancement for anyone who "uses or carries a firearm" during and in relation to a drug trafficking crime applies when the gun in question was locked in the glove box of the defendant's car. A 5-to-4 majority held that the "carry in a car" sense of the word "carry" was ordinary, while the "carry on your person" sense of "carry" was a "different, somewhat special meaning of the word 'carry.' " To reach this conclusion, the court turned to a variety of dictionaries:

Consider first the word's primary meaning. The Oxford English Dictionary gives as its first definition "convey, originally by cart or wagon, hence in any vehicle, by ship, on horseback, etc." 2 Oxford English Dictionary 919 (2d ed. 1989); see also Webster's Third New International Dictionary 343 (1986) (first definition: "move while supporting (as in a vehicle or in one's hands or arms)"); Random House Dictionary of the English Language Unabridged 319 (2d ed. 1987) (first definition: "to take or support from one place to another; convey; transport").

The emphasis on each "first" in the passage above is in the original. The trouble with this line of reasoning is that, contrary to a commonly shared belief, dictionaries such as the Webster's Third New International Dictionary (Webster's Third) and the Oxford English Dictionary (the OED) don't rank their senses in terms of ordinariness—they list them historically with the first sense attested in the lexicographer's citation files listed first. But the statute the court is interpreting wasn't enacted in 1320 (the date of the OED's first recorded use of "carry"); it was enacted in 1968. Dictionary editors caution against relying on the internal structure of a dictionary entry (its macrostructure) to draw inferences about meaning. The editors of Webster's Third make this point in the front matter of their dictionary (at 17a):

The system of separating by numbers and letters reflects something of the semantic relationship between various senses of a word. It is only a lexical convenience. It does not evaluate senses or establish an enduring hierarchy of importance among them. The best sense is the one that most aptly fits the context of an actual genuine utterance.

The argument based on the ranking of senses is not the Muscarello majority's only reliance on dictionaries. The Muscarello majority also cites a pair of etymological dictionaries for the proposition that "carry" traces its origin from the "Latin 'carum,' which means 'car' or 'cart,' " and from "Old French 'carier' and the late Latin 'carricare,' which meant to 'convey in a car.' " The precise premises of the majority's analysis are left implicit. But the implicit point seems clear—the etymology of the verb "carry" confirms that the "transport" sense of the term is ordinary and the personally "bear" sense is unusual. This common assumption that a word's ordinary meaning can be found in its etymology doesn't hold up well to scrutiny. By this same reasoning, December would be the 10th month, not the 12th month; an anthology would be a bouquet of flowers; and "skirt" and "shirt" would mean the same thing.

We can see similar problems arise in the Supreme Court's more recent decision in Taniguchi v. Kan Pacific Saipan, LTD. In Taniguchi, the Supreme Court was faced with the question of whether a litigation expert who is paid to translate written documents from one language to another is an interpreter under a statute authorizing an award of costs for prevailing parties who utilize them in litigation. The Taniguchi opinion appears, at first glance, to employ dictionaries in a less arbitrary way. Justice Samuel A. Alito Jr. does not turn to sense ranking or etymology. He presents an informal "survey" of dictionary definitions, asserting that "only a handful" of dictionaries include the "written translator" sense of "interpreter," but "all" of them speak of an oral translator. And he says that the sense dividers in the cited dictionaries confirm the court's holding—in designating the "oral translator" notion as one that is "especially" indicated and flagging the "written translator" sense as "obsolete."

Yet this approach is still problematic. The "survey" of dictionaries is far from systematic. Alito presents his own set of dictionaries without indicating on what basis some dictionaries were included and others excluded. And within the cited dictionaries Alito sometimes cites a definition of the noun "interpreter" and sometimes cites a definition of the verb "interpret." We cannot tell from the opinion whether the "written translator" sense of "interpreter" is less often listed in a real "survey" of dictionaries because we are not presented with an actual survey of dictionaries.

Not all of the dictionaries cited by the majority designate "written translator" as obsolete or "oral translator" as a special sense. At least one definition mentioned in the majority opinion explicitly encompasses the written sense of the term, without any indication of obsolescence.

Moreover, dictionaries tell us very little about the basis for the "obsolete" and "especially" sense designations referenced by the Taniguchi majority. And ultimately, such designations must be made on the basis of some underlying data that is unavailable to the reader of the dictionary. These designations may give us a clue as to the type of material a given lexicographer has in his or her citation file. But without seeing the data for ourselves (or knowing how it was assembled), we have reason to be skeptical that a dictionary's conclusions about special or obsolete definitions can reliably map onto our questions about ordinary meaning.

This is not to suggest that dictionaries are never useful in interpreting legal texts. Judges can turn to dictionaries to define unknown terms or to show that a contested usage is attested in the language. But if we are going to seek the ordinary meaning of the words of statute; take into account questions of syntactic, semantic and pragmatic context; and account for variations in historical usage, speech community and register, we will have to look evidence of meaning beyond the pages of a dictionary. As we will demonstrate in the coming days, this sort of evidence can be found in a corpus.