Like other languages, English has ways of expressing evidentiality, in other words, ways of expressing the provenance of information from a knowledge base. One such form is the English evidential -ly adverb. The evidential -ly adverbs analysed in this book are: reportedly, purportedly, allegedly, supposedly, evidently, presumably, seemingly, apparently, obviously, clearly, visibly. Using the NOW corpus (News on the Web), the adverbs were extracted with context from UK newspapers. The theoretical framework adopted for the analysis of these adverbs is Functional Discourse Grammar (FDG), a structural-functional approach with a layered hierarchy. Tests using FDG layers are applied to determine the categorization of evidential -ly adverbs into FDG evidential subcategories: reportative, inferential, deductive and event perception. The distribution and behaviour of these adverbs in main clauses, clausal complements and noun phrases are explored by applying FDG tools. It has appeared that some adverbs belong to more than one evidential subcategory and are thus hosted by more than one FDG layer. The meaning of these chameleon-like adverbs is determined by the local context. The FDG analysis and its tests have confirmed the categorization and meaning of the English evidential adverbs. Although the adverbs belong to different layers with different meanings, they all serve to mark a knowledge base as source of information.
