Individuals and groups have constructed their own artificial languages, for practical, experimental, personal, or ideological reasons. International auxiliary languages are generally constructed languages that strive to be easier to learn than natural languages; other constructed languages strive to be more logical ("loglangs") than natural languages; a prominent example of this is Lojban. (The Logical Language Group (LLG) ) .Some languages, most constructed, are meant specifically for communication between people of different nationalities or language groups as an easy-to-learn second language. Several of these languages have been constructed by individuals or groups. Natural, pre-existing languages may also be used in this way - their developers merely catalogued and standardized their vocabulary and identified their grammatical rules. These languages are called naturalistic. One such language, Latino Sine Flexione, is a simplified form of Latin. Two others, Occidental and Novial, were drawn from several Western languages. Some writers, such as J. R. R. Tolkien, have created fantasy languages, for literary, artistic or personal reasons. The fantasy language of the Klingon race (a warrior race in the fictional Star Trek universe ) has in recent years been developed by fans of the Star Trek series, including a vocabulary and grammar.

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.