Research on the effects of bilingualism on the structure of the brain has so far yielded variable patterns. Although it cannot be disputed that learning and using additional languages restructures the brain, the reported effects vary considerably, including both increases and reductions in grey matter volume and white matter diffusivity. This presentation reviews the available evidence and compares it to patterns from other domains of skill acquisition, culminating in the Dynamic Restructuring Model, a theory which synthesises the available evidence from the perspective of experience-based neuroplasticity. New corroborating evidence is also presented from healthy young and older bilinguals, and the presentation concludes with the implications of these effects for the ageing brain.