Linguistics is the scientific study of human language. Linguists gather information about sounds and sound patterns, about words and word patterns. They look at how words form sentences and how language is used to communicate. Linguists who focus on the form of language look at phonetics, phonology, morphology, and syntax. Linguists also look at how form changes over time (historical linguistics), compare the languages of the world to each other (language typology), and also compare writing systems (orthography). Many linguists look at how language connects to meaning (semantics and pragmatics), cognition (language acquisition, psycholinguistics, and neurolinguistics), and society (anthropological linguistics and sociolinguistics).