ABSTRACT
This chapter describes what is involved in learning a word, and what kinds of explicit and implicit knowledge learners of English acquire when they learn vocabulary. When people discuss words, it is important to be clear about whether they are talking about the word form or the meanings. It is usual to consider one form of a word as a headword. When we count the different words in a text or when we try to estimate the number of words a person knows, it is usual to group together into a lemma the inflected forms which belong to the same word class. Semantics is the study of meaning relationships and is a huge field of study in its own right. Language learners need to learn that something caused something to happen, or belong to different classes or categories. Huge numbers of English words contain Latin and Greek affixes which entered English as part of word borrowings from these classical languages.
