Diagramming for Statutory Interpretation

Juana Summers of NPR detailed this week the use of sentence diagramming, a grammar technique once widely used in America,

Burns Florey and other experts trace the origin of diagramming sentences back to 1877 and two professors at Brooklyn Polytechnic Institute. In their book, Higher Lessons in English,Alonzo Reed and Brainerd Kellogg made the case that students would learn better how to structure sentences if they could see them drawn as graphic structures.

After Reed and Kellogg published their book, the practice of diagramming sentences had something of a Golden Age in American schools.

The practice fell into disuse by the 60’s, and received vocal opposition from educators by the mid-80s. Summers wonders if there are some limited applications for which it could still be used today. For example, those with a visual learning style would probably benefit from observing these, and kinaesthetic learners may even enjoy mapping sentences in graphic format.

How this diagramming works can be demonstrated with this line from Planet of the Apes (the 1968 original),

Planet of the Apes

The colour coordination of the various words are described as follows:

Key 1 Key 2

Although sentence diagramming was intended to help students with how to better structure sentences, it can also be helpful in understanding the relationship between words. We face unique challenges when dealing with sentences in law, as best characterized by Judge Marvin Frankel in 1972, Criminal Sentences – Law Without Order,

The almost wholly unchecked and sweeping powers we give to judges in the fashioning of sentences are terrifying and intolerable for a society that professes devotion to the rule of law.

Law students also struggle with sentence deconstruction, what we call parsing in law, as one student illustrated by pointing to the meaning of “purposely entered at night,”

“Purposely entered at night.” It depends on whether you parse the law as purposely (entered at night) or (purposely entered) at night. That is, did the guy know that he entered, and know it was at night, or did he know that he entered, and it was at night (whether he knew that or not). The joys of statutory construction. And I suppose an argument could be made that “purposely” implies something more than mere knowledge, that it might even require that he made a conscious choice to enter at night rather than during the day.

You either love or hate this type of exercise. Either way, you’re stuck with it when practising law.

Sentence diagramming may assist us in deciphering the often obscure passages we come across in our profession, or at the very least, give us alternative explanations as to what they might mean. And for many of us, in a nutshell that is exactly what lawyering is.

The reason why the relationship between words, and not just the meaning of words themselves, are important in statutory interpretation is that the syntactic relationships among the constituent words provides nuance that an isolated examination of the words itself invariably overlooks.

Craig Hoffman states in Parse the Sentence First: Curbing the Urge to Resort to the Dictionary when Interpreting Legal Texts,

In thinking about sentence interpretation, linguists have pointed out that sentences are not mere word strings: that is, interpreting a sentence is much more than defining the words that comprise it. The key to sentence meaning is to understand how the grammar generates and interprets the syntactic and semantic relation- ships among the phrasal categories that the sentence contains.

Hoffman examines several U.S. Supreme Court cases, parses importance sentences in questions, diagrams the sentences to illustrate the relationship between the words, and demonstrates have several faulty conclusions have been made through improper interpretation. He concludes,

Although dictionaries are useful for divining the derivations and denotations of individual lexical items, dictionaries are not so useful when interpreting complex phrases in legal texts. Lawyers and judges resort to dictionaries out of habit and ignorance. By looking carefully at the U.S. Supreme Court’s uncritical use of Dictionary Method, it becomes clear that the habitual resort to the dictionary is far from harmless. As the legal profession becomes more aware of the practi- cal benefits of using Linguistic Method when interpreting legal texts, statutory interpretation can become more consistent with linguistic in- tuitions and, consequently, more likely to create stable and informed precedent.

If the task of diagramming a statute or judicial decision still seems onerous, we can probably expect some form of algorithm to be developed in the near future which will help do this mapping for us.

Hung et al. state in the International Journal on Natural Language Computing,

Machine translation can work well for simple sentences but a machine translation system faces difficulty while translating long sentences, as a result the performance of the system degrades. Most legal sentences are long and complex, the translation model has a higher probability to fail in the analysis, and produces poor translation results.

By splitting complex legal sentences into smaller segments, Hung et al. were able to more better determine the correct syntactic structure and reduce ambiguity. The four cases of logical structure in legal sentences they identify is as follows:

Structure of Legal Sentences

They apply this approach to translate legal sentences in English to Japanese more accurately than traditional statistical machine translation.

Unfortunately, many of us need these translations when converting (legal) English sentences into (colloquial) English. Mapping it out is just a more convenient way to understand the relationship between the words, and far more concise than a legal brief explaining it.


  1. Lecteur Lectrice

    French syntax seems to produce clearer legal writing.

    I often notice that statutory interpretation is much easier when I resort to the French version of a federal statute. This is especially true in the Income Tax Act, where in English we often find a preamble, then some pages of subsections, then the “postamble”. Rather than bouncing back and forth between the scaffolding at the extremities, I turn to the French version, and the same provision always seems to roll out in an orderly fashion, with all the scaffolding together at the start and then the other bits following behind.

    So learn French if you work with Federal law, I guess!