It was a reaction to the abstract notion of language – as a monolithic, decontextualised, static entity – propagated by Chomsky, and it was conceived as a broad and interdisciplinary framework. In his use of 'ecology' as a metaphor from biology in linguistics, Haugen formulated ten questions which together comprehensively address factors pertaining to the positioning of languages in their environment. Each of these relates to a traditional sub-field of the study of language – encompassing historical linguistics, linguistic demography, sociolinguistics, contact, variation, philology, planning and policy, politics of language, ethnolinguistics, and typology – and each of them intersects with one or more of the other sub-fields.