Esperanto is the most widely spoken artificial language. The name derives from Doktoro Esperanto, the pseudonym under which L. L. Zamenhof published the first book of Esperanto, the Unua Libro, in 1887. The word esperanto means 'one who hopes'. Zamenhof's goal was to create an easy and flexible language that would serve as a universal second language to foster peace and international understanding. Esperanto has a very regular structure. Words are often made from many other roots, and in this way the number of words which one must memorise is made much smaller. The language is phonetic, and the rules of pronunciation are very simple, so that everyone knows how to pronounce a written worde and vice-versa.Esperanto has had continuous usage by a community estimated at between 100,000 and 2 million speakers for over a century. By most estimates, there are approximately a thousand native speakers. No country has adopted the language officially. Today, Esperanto is employed in world travel, correspondence, cultural exchange, conventions, literature, language instruction, television (Internacia Televido), and radio broadcasting. Esperanto is also a language of internet websites, which can be explored from the Esperanto interface of Google Search.

Psycholinguistics is the psychology of language and the study of the psychological and neurobiological factors that enable humans to acquire, use, and understand language. Psycholingusitics research makes use of biology, neuroscience, cognitive science, and information theory to study how the brain processes language. There are a number of subdisciplines; for example, as non-invasive techniques for studying the neurological workings of the brain become more and more widespread, neurolinguistics has become a field in its own right.The study of word recognition and reading examines the processes involved in the extraction of orthographic, morphological, phonological, and semantic information from patterns in printed text. Psycholinguistics covers the cognitive processes that make it possible to generate a grammatical and meaningful sentence out of vocabulary and grammatical structures, as well as the processes that make it possible to understand utterances, words, text, etc. Developmental psycholinguistics studies children's ability to learn language.