percent in "Politics and the English Language". Clearly he found the construction useful in spite of his advice to avoid it as much as possible". Defining "passive" In the field of linguistics, the term passive is applied to a wide range of grammatical structures. Linguists therefore find it difficult to define the term in a way that makes sense across all human languages. The canonical passive in European languages has the following properties: The subject is not an agent. There is a change in: word order; or in nominal morphology—the form of the nouns in the sentence. There is specific verbal morphology—a particular form of the verb indicates passive voice. The problem arises with non-European languages. Many constructions in these languages share at least one property with the canonical European passive, but not all. While it seems justified to call these constructions passive when comparing them to European languages' passive constructions, as a whole the passives of the world's languages do not share a single common feature. R. M. W. Dixon has defined four criteria for determining whether a construction is a passive: It applies to underlying transitive clauses and forms a derived intransitive. The entity that is the patient or the object of the transitive verb in the underlying representation (indicated as O in linguistic terminology) becomes the core argument of the clause (indicated as S, since the core argument is the subject of an intransitive). The agent in the underlying representation (indicated as A) becomes a chômeur, a noun in the periphery that is not a core argument. It is marked by a non-core case or becomes part of an adpositional phrase, etc. This can be omitted, but there is always the option of including it. There is some explicit marking of the construction. Dixon acknowledges that this excludes some constructions labeled as passive by some linguists. Adversative passive In some languages, including several Southeast Asian languages, the passive voice is sometimes used to indicate that an action or event was unpleasant or undesirable. This so-called adversative passive works like the ordinary passive voice in terms of syntactic structure—that is, a theme or instrument acts as subject. In addition, the construction indicates adversative affect, suggesting that someone was negatively affected. In Japanese, for example, the adversative passive (also called indirect passive) indicates adversative affect. The indirect or adversative passive has the same form as the direct passive. Unlike