Lexical bundles: functions and categories
Multi-word units and metaphor in ESP
Lexical bundles are strings of three or more words that occur frequently (Biber et al., 1999). Biber (2006, p. 134) notes that lexical bundles tend not to be idiomatic. Bundles can be complete grammatically (for example, on the other hand) or not (in the case of the) (Paquot & Granger, 2012, p. 138). Analysis by Biber et al. (1999) showed that 60% of the lexical bundles in academic prose are phrasal (in the case of; as a result of), parts of noun phrases (on the basis of), or prepositional phrases (on the other hand). Just like single-word research, frequency criteria are usually applied to the selection of lexical bundles from corpora. Some studies have used frequency cut off points of ten occurrences per million words (Biber et al., 1999), 20 per million (Biber, 2006; Cortes, 2013; Hyland, 2008) and up to 40 occurrences per million words of text (Biber & Barbieri, 2007). The range of occurrence is also taken into account in some way, particularly in studies involving multiple disciplines or subject areas (see, for example, Simpson-Vlach & Ellis, 2010).
Analyses of corpora for academic purposes showed that lexical bundles occurred more often in classroom discourse than textbooks and academic prose (Biber et al., 2004). Biber (2006) explains that classroom teaching discourse uses bundles from each of the three main categories (stance, discourse organisation and reference) because
lexical bundles are useful for instructors who need to organise and structure discourse which is at the same time informational, involved, and produced with real-time production constraints.
These categories can be broken down into more fine-grained categories. For example, discourse organising bundles include topic introduction and topic focus, and topic elaboration and topic clarification (Biber, 2006). Here are some examples from Biber and Barbieri (2007) of these categories:
Topic introduction bundles: What I want to do is quickly run through the exercise… Topic elaboration/clarification bundles: It has to do with the START talks, with the Russians, Identification/focus bundles: For those of you who came late I have the, uh, the quiz.