Abstract
The emergent field of multilingual research has had a much greater impact on linguistics than many might have thought possible. The research subject of ‘more than one language in one mind’, for example, represents not merely an additive function, but rather a separate challenge altogether, thus breaking the boundaries of traditional methods of description. This and other findings have shaken some of the very foundations of linguistics: it affects for example the view of clearly definable languages with their modules, and ultimately the separability of languages in the mind of an individual. When the focus is on the multilingual individual, the concept of separable individual languages can no longer be strictly applied.