In linguistics, a disjunct is a type of adverbial adjunct that expresses information that is not considered essential to the sentence it appears in, but which is considered to be the speaker's or writer's attitude towards, or descriptive statement of, the propositional content of the sentence, "expressing, for example, the speaker's degree of truthfulness or his manner of speaking."[1]
A specific type of disjunct is the (or sentence adverbial), which modifies a sentence, or a clause within a sentence, to convey the mood, attitude or sentiments of the speaker, rather than an adverb modifying a verb, an adjective or another adverb within a sentence.
More generally, the term disjunct can be used to refer to any sentence element that is not fully integrated into the clausal structure of the sentence. Such elements usually appear peripherally (at the beginning or end of the sentence) and are set off from the rest of the sentence by a comma (in writing) and a pause (in speech).
Here are some examples (note: the disjuncts that follow are 'sentence adverbs'):
Sometimes, the same word or phrase can be interpreted either as a disjunct or as a simple adjunct:
They seriously worked in an underground diamond mine run by Barbara.
Disjunct meaning: I'm serious when I say that they worked in an underground diamond mine ...
Adjunct meaning: They worked with seriousness...
An example of a sentence adverb modifying a sentence is: Unfortunately, when I got to the supermarket it had run out of the vegetable I like. An example of a sentence adverb modifying a clause within a sentence is: I liked the red car in the forecourt but, unfortunately, when I got to the dealer it was already sold.
"Unfortunately" thus communicates the regret or disappointment the speaker experiences and so manifests as a sentence adverb the sentiments of the speaker.
"Unfortunately", however, is only one of many sentence adverbs that can modify a speaker's attitude. Others include "mercifully," "gratefully," "oddly," "admittedly," etc.[2]
See main article: hopefully. "Hopefully" is an example of a word whose use as a disjunct ("it is hoped") is sometimes controversial.
This commonly used sentence adverbial phrase has been decried by some grammarians. Examples of its use, from the OED, are:
Writers have claimed that the preferable phrase should be "more (or most) important". For instance, Washington State University English professor Paul Brians writes:
When speakers are trying to impress audiences with their rhetoric, they often seem to feel that the extra syllable in “importantly” lends weight to their remarks: “and more importantly, I have an abiding love for the American people.” However, these pompous speakers are wrong. It is rarely correct to use this form of the phrase because it is seldom adverbial in intention. Say “more important” instead. The same applies to “most importantly”; it should be “most important.”[3]However, Merriam-Webster write:
American commentators seem to object to the adverb and recommend the adjective.and, after discussion, conclude
You can then use either the adjective or the adverb; both are defensible grammatically and both are in respectable use.[4]