Randy Haddock

…knowing two languages is much more than simply knowing two ways of speaking….it seems evident that the mind of a speaker who has in some way attached two sets of linguistic details to a conceptual representation, whether in a unified or discretely arranged system, has entertained possibilities that the monolingual speaker has had no need to entertain. The enriching aspect of bilingualism may follow directly from its most maddening complication: it is precisely because the structures and concepts of different languages never coincide that the experience of learning a second language is so spectacular in its effects.