inquiry and research.Divisions based on nonlinguistic factors studiedAlongside the structurally motivated domains of study are other fields of linguistics. These fields are distinguished by the kinds of nonlinguistic factors that they consider:Applied linguistics, the study of language-related issues applied in everyday life, notably language policies, planning, and education. (Constructed language fits under Applied linguistics.)Biolinguistics, the study of natural as well as human-taught communication systems in animals, compared to human language.Clinical linguistics, the application of linguistic theory to the field of Speech-Language Pathology.Computational linguistics, the study of computational implementations of linguistic structures.Developmental linguistics, the study of the development of linguistic ability in individuals, particularly the acquisition of language in childhood.Evolutionary linguistics, the study of the origin and subsequent development of language by the human species.Historical linguistics or diachronic linguistics, the study of language change over time.Language geography, the study of the geographical distribution of languages and linguistic features.Linguistic typology, the study of the common properties of diverse unrelated languages, properties that may, given sufficient attestation, be assumed to be innate to human language capacity.Neurolinguistics, the study of the structures in the human brain that underlie grammar and communication.Psycholinguistics, the study of the cognitive processes and representations underlying language use.Sociolinguistics, the study of variation in language and its relationship with social factors.Stylistics, the study of linguistic factors that place a discourse in context.Semiotics is not a discipline within linguistics; rather, it investigates the relationship between signs and what they signify more broadly. From the perspective of semiotics, language can be seen as a sign or symbol, with the world as its representation.Variation and universalityMuch modern linguistic research, particularly within the paradigm of generative grammar, has concerned itself with trying to account for differences between languages of the world. This has worked on the assumption that if human linguistic ability is narrowly constrained by human biology, then all languages must share certain fundamental properties.In generativist theory, the collection of fundamental properties all languages share are referred to as universal grammar (UG). The specific characteristics of this universal grammar are a much debated topic. Typologists and non-generativist linguists usually refer simply to language universals, or universals of language.Similarities between languages can have a number of different origins. In the simplest case, universal properties may be due to universal aspects of human experience. For example, all humans experience water, and all human languages have a word for water. Other similarities may be due to common descent: the Latin language spoken by the Ancient Romansdeveloped into Spanish in Spain and Italian in Italy; similarities between Spanish and Italian are thus in many cases due to both being descended from Latin. In other cases, contact between languages particularly where many speakers are bilingual can lead to much borrowing of structures, as well as words. Similarity may also, of course, be due to coincidence. English much and Spanish mucho are not descended from the same form or borrowed from one language to the other;[13] nor is the similarity due to innate linguistic knowledge (see False cognate).Arguments in favor of language universals have also come from documented cases of sign languages