Rules of Language

When courts interpret statutes and contracts, they often rely on established rules of language to clarify the meaning of ambiguous terms and ensure that legal documents are understood as intended. These rules help judges and legal practitioners deduce the proper application of the law or the intent of contractual provisions. The three primary rules of language used in legal interpretation are ejusdem generis, expressio unius est exclusio alterius, and noscitur a sociis.

Ejusdem Generis
Ejusdem generis, which means "of the same kind" in Latin, is a rule used to interpret general words that follow specific ones in a list. According to this rule, when a general term follows a list of specific items, the general term is understood to include only items of the same type as the specific ones listed.

In statutory interpretation, if a law mentions "cars, trucks, motorcycles, and other vehicles", the term "other vehicles" would be interpreted to include vehicles similar to cars, trucks, and motorcycles, such as scooters or vans, but not airplanes or boats, which are fundamentally different.

In the case of Powell v Kempton Park Racecourse (1899), the court used the ejusdem generis rule to determine that the term "other places" in a statute that listed "house, office, room or other place" for betting purposes did not include outdoor betting rings, as the specific terms listed referred to indoor places.

Expressio Unius Est Exclusio Alterius
Expressio unius est exclusio alterius, Latin for "the expression of one thing is the exclusion of another", is a rule stating that if specific items are listed in a statute or contract, items not listed are assumed to be excluded.

If a law specifies "cats and dogs" in a regulation about pet licenses, it implies that animals not mentioned, such as birds or reptiles, are not covered by the regulation. This rule helps narrow down the scope of general terms to only include the explicitly mentioned items.

In Tempest v Kilner (1846), the court applied this rule to a statute concerning the sale of "goods, wares, and merchandise". The court held that the term did not include stocks and shares because they were not expressly mentioned in the statute.

Noscitur A Sociis
Noscitur a sociis, meaning "it is known by its associates" in Latin, is a rule stating that the meaning of a word can be determined by the words surrounding it. This principle suggests that words should be interpreted in the context of the entire phrase or sentence.

If a statute refers to "property, houses, and estates", the term "property" would be interpreted in the context of real estate rather than personal property, as "houses" and "estates" suggest a real estate context.

In Muir v Keay (1875), the court used noscitur a sociis to interpret the phrase "entertainment" in a statute. The court concluded that "entertainment" included not only theatrical performances but also cafes and public houses, as these were similar types of venues mentioned in the same context.

In summary, these three rules of language are essential tools for courts in interpreting statutes and contracts. They help clarify ambiguous terms, ensure consistency in legal interpretation, and align the understanding of legal texts with the intended scope and context. By applying these principles, judges can provide more precise and just rulings, contributing to a fairer and more predictable legal system.