Аннотация:The paper examines the underlying origin of English modal adverbs known in linguistics also as disjuncts. It is acknowledged that disjuncts are semantic derivations of identical adverbs functioning as adverbial modifiers of manner. We assume that disjuncts (certainly, frankly, etc.) have passed through a number of reconstructive operations before they come to be used as such, i.e. parentheses expressing the speaker's attitude to the whole utterance. The basic aim of the research is to find out what constructions underlie these lexical units and what kind of reconstructions the latter undergo before they come to be used as disjuncts. The research is carried out in the framework of cognitive and transformational grammar. The results of the study allow us to state that lexical units of this type are the outcome of various kinds of reconstructions, which, in addition to ellipsis, include deletion, substitution, movement, expansion, etc. Each of these reconstructions generally recognized as compression defines a transformational step which the underlying structures take before obtaining their final form as single units. The paper also examines cases with some adjectives occurring in the initial position, which makes them identical to the respective adverbs functioning as disjuncts.