The neural basis of language, from acquisition to its functions such as grammar and speech to its pathological issues, has been under scientific exploration for well over a century. Findings so far have mainly linked language to the frontal and temporal lobes of the cortex, extending from the original 19th century association with Broca and Wernicke’s areas. Multilingualism, once discouraged as a “distracting influence on children” has slowly been described as a major driver of neuroplastic change in the brain. Since the advent of functional magnetic resonance imaging (fMRI), an increasing number of studies have linked multilingualism to both structural and functional changes, not only in the primary frontotemporal region. Since language employs an extremely wide variety of cognitive functions (from hearing to processing to speech), a wide cortical network is stimulated when learning and using non-native language. The neuroplasticity induced by multilingualism, interestingly, seems to be dependent on several factors: age of acquisition, combination of languages, level of fluency etc., all leading to significantly different adaptations in the brain. Of particular medical interest is the link between multilingualism and dementia, as many studies suggest a neuroprotective effect of language acquisition and second language use. This review summarises some of the most relevant findings in the field over the past two decades, as well as a selection of opinions by the prominent experts in bilingualism and neurolinguistics.