This chapter will be concerned with lexical progression at the individual level, that is with first and second language acquisition. In the conclusion, the relation of these areas to other types of progression and to regression will be briefly discussed. The chapter will open with a brief presentation of a general framework for studying the organization of the lexicon from a crosslinguistic perspective, since a proper understanding of language structure is a prerequisite for any deeper understanding of the learning process and more general explanatory factors.

THE ORGANIZATION OF THE BASIC LEXICON

Frequency ranking and semantic field classification

The fundamental problem with the lexicon is its size. In any full-blown natural language, the number of lexical items which are actively commanded by a native speaker is in the tens of thousands. In order to give a holistic account of lexical structure, a method must be found to delimit a set of basic words which represent the lexical core of a given language.

A simple method which has been shown to be very useful is frequency ranking within word classes. Words within each of the four open word classes are ranked with respect to frequency and classified into semantic fields. It is then possible to compare languages with respect to the meanings of the words belonging to a certain part of speech at different frequency ranks (e.g. the 10, 20, 50, or 100 most frequent verbs).