because basic word order type corresponds with other syntactic parameters, such as the relative order of nouns and adjectives, or of the use of prepositions Language is a structured system of communication that consists of grammar and vocabulary. It is the primary means by which humans convey meaning, both in spoken and signed forms, and may also be conveyed through writing. Human language is characterized by its cultural and historical diversity, with significant variations observed between cultures and across time. Human languages possess the proper Languages can be classified in relation to their grammatical types. Languages that belong to different families nonetheless often have features in common, and these shared features tend to correlate. For example, languages can be classified on the basis of their basic word order, the relative order of the verb, and its constituents in a… As an object of linguistic study, "language" has two primary meanings: an abstract concept, and a specific linguistic system, e.g. "French". The Swiss linguist Ferdinand de Saussure, who defined the modern discipline of linguistics, first explicitly formulated the distinction using the French word langage for language as a concept, langue as a specific instance of a language system, and parole for the concrete use of speech in a particular language. When speaking of language as a general concept, definitions can be used which stress different aspects of the phenomenon. This structuralist view of language was first introduced by Ferdinand de Saussure, and his structuralism remains foundational for many approaches to language. Some proponents of Saussure's view of language have advocated a formal approach that studies language structure by identifying its basic elements and then by presenting a formal account of the rules according to which the elements combine in order to form words and sentences. The main proponent of such a theory is Noam Chomsky, the originator of the generative theory of grammar, who has defined language as the construction of sentences that can be generated using transformational grammars. Saussure also introduced several basic dimensions of linguistic analysis that are still fundamental in many contemporary linguistic theories, such as the distinctions between syntagm and paradigm, and the Langue-parole distinction, distinguishing language as an abstract system (langue), from language as a concrete manifestation of this system (parole). === Modern linguistics === In the 1960s, Noam Chomsky formulated the generative theory of language. According to this theory, the most basic form of language is a set of syntactic rules that is universal for all humans and All languages, for instance, make a basic distinction between a group of words that prototypically denotes things and concepts and a group of words that prototypically denotes actions and events. The first group, which includes English words such as "dog" and "song", are usually called nouns. The second, which includes "think" and "sing", are called verbs. Another common category is the adjective: words that describe properties or qualities of nouns, such as "red" or "big". Word classes can be "open" if new words can continuously be added to the class, or relatively "closed" if there is a fixed number of words in a class. This is sometimes called agreement. For example, in many Indo-European languages, adjectives must cross-reference the noun they modify in terms of number, case, and gender, so that the Latin adjective bonus, or "good", is inflected to agree with a noun that is masculine gender, singular number, and nominative case. In many polysynthetic languages, verbs cross-reference their subjects and objects. In these types of languages, a single verb may include information that would require an entire sentence in English. Syntactical rules determine how word order and sentence structure is constrained, and how those constraints contribute to meaning. For example, in English, the two sentences "the slaves were cursing the master" and "the master was cursing the slaves" mean different things, because the role of the grammatical subject is encoded by the noun being in front of the verb, and the role of object is encoded by the noun appearing after the verb. Conversely, in Latin, both Dominus servos vituperabat and Servos vituperabat dominus mean "the master was reprimanding the slaves", because servos, or "slaves", is in the accusative case, showing that they are the grammatical object of the sentence, and dominus, or "master", is in the nominative case, showing that he is the subject. Latin uses morphology to express the distinction between subject and object, whereas English uses word order. Another example of how syntactic rules contribute to meaning is the rule of inverse word order in questions, which exists in many languages. To the right is a graphic representation of the syntactic analysis of the English sentence "the cat sat on the mat". The sentence is analyzed as being constituted by a noun phrase, a verb, and a prepositional phrase; the prepositional phrase is further divided into a preposition and a noun phrase, and the noun phrases consist of an article and a noun. The reason sentences can be seen as being composed of phrases is because each phrase would be moved around as a single element if syntactic operations were carried out. Word order type is relevant as a typological parameter, because basic word order type corresponds with other syntactic parameters, such as the relative order of nouns and adjectives, or of the use of prepositions or postpositions. Such correlations are called implicational universals. For example, most (but not all) languages that are of the SOV type have postpositions rather than prepositions, and have adjectives before nouns. All languages structure sentences into Subject, Verb, and Object, but languages differ in the way they classify the relations between actors and actions.