Avec Alex Boulton Research has consistently shown that a few thousand word families can be enough to understand most written or spoken text (e.g. Nation, 2006; Van Zeeland & Schmitt, 2013). The implication is that these frequent items need to be learned and to be learned thoroughly. However, diminishing returns set in, and other tools are required for the many tens of thousands of other items, chief among which being various types of dictionaries which are among the most widely-used tools for foreign and second (L2) language learning. This chapter begins with a discussion of dictionaries themselves and major issues affecting their development over the last few decades in particular; these include the increasing use of empirical data, especially in the form of corpora, and the appearance of monolingual learner dictionaries in addition to bilingual and other dictionary types. It then moves on to a discussion of research into learner use of dictionaries, especially as a reference resource for encoding and decoding, as well as their impact on language learning itself.
Boulton, A., & De Cock, S. (2017). Dictionaries as aids for language learning. In P Hanks & G.-M. de Schryver (eds.) (ed.), International handbook of lexis and lexicography. Springer. https://hdl.handle.net/2078.5/223755