Neurolinguistics

Neurolinguistics examines how the human brain controls language—how we understand, produce, and learn it. This interdisciplinary field pulls methods and theories from neuroscience, linguistics, cognitive science, communication disorders, and neuropsychology. Researchers come from diverse backgrounds, bringing different experimental techniques and theoretical perspectives. Much of the work is guided by models from psycholinguistics and theoretical linguistics, focusing on how the brain can carry out the processes those fields propose are needed for language. Neurolinguists study the physiological mechanisms behind language-related information processing and test linguistic and psycholinguistic theories using aphasiology, brain imaging, electrophysiology, and computer modeling.

The field’s roots lie in 19th-century aphasiology, which examines language deficits (aphasias) caused by brain damage. Aphasiology links structure to function by analyzing how brain injuries affect language processing. Paul Broca, a French surgeon, was among the first to connect a specific brain area to language. After autopsying individuals with speech difficulties, he found most had lesions on the left frontal lobe—now called Broca’s area. While phrenologists had earlier claimed that different brain regions handled different functions and that language was mainly frontal, Broca’s work provided the first empirical evidence for such a link, described as epoch-making and pivotal for neurolinguistics and cognitive science. Later, Carl Wernicke proposed that different brain areas specialize in different linguistic tasks: Broca’s area for motor speech production, and Wernicke’s area for auditory speech comprehension. Their work founded aphasiology and the idea that language can be studied through brain anatomy. Early aphasiology also benefited from Korbinian Brodmann’s early 20th-century mapping of the brain’s surface into numbered areas based on cell structure and function—Brodmann areas still widely used today.

The term “neurolinguistics” was coined in the late 1940s and 1950s, attributed to Edith Crowell Trager, Henri Hecaen, and Alexandr Luria. Luria’s 1976 book *Basic Problems of Neurolinguistics* is likely the first with “neurolinguistics” in its title. Harry Whitaker popularized the field in the United States in the 1970s, founding the journal *Brain and Language* in 1974. While aphasiology remains the historical core, the field has broadened recently, thanks partly to new brain imaging technologies (PET and fMRI) and time-sensitive electrophysiological techniques (EEG and MEG), which reveal brain activation patterns during language tasks. Electrophysiological methods became viable for language study in 1980 with the discovery of the N400, a brain response sensitive to semantic issues in comprehension. The N400 was the first language-relevant event-related potential identified, and since then EEG and MEG have become widely used in language research.

Neurolinguistics is closely tied to psycholinguistics, which explores cognitive language mechanisms using experimental psychology. Today, theories from both fields inform each other, and collaboration is common. Much neurolinguistic work tests and evaluates theories from psycholinguists and theoretical linguists. In general, theoretical linguists propose models of language structure and information organization, psycholinguists propose models of how language is processed in the mind, and neurolinguists analyze brain activity to infer how biological structures (neuron populations and networks) implement those processing algorithms. For example, sentence processing experiments use ELAN, N400, and P600 brain responses to see how physiological responses reflect different predictions from psycholinguistic models, such as Janet Fodor and Lyn Frazier’s serial model or Theo Vosse and Gerard Kempen’s unification model. Neurolinguists can also generate new predictions about language structure and organization by generalizing from knowledge of neurological structures to language structure. Research covers all major linguistic subfields, addressing where language information is processed, how processing unfolds over time, how brain structures relate to language acquisition and learning, and how neurophysiology contributes to speech and language.