Lexis
Lexis refers to the total stock of words and word-like units in a language, or in a speaker's repertoire. In ELT, "lexis" is preferred over "vocabulary" because it captures a broader reality: language is not just single words but multi-word units — collocations, formulaic sequences, phrasal verbs, and idioms — stored and processed as wholes.
Lexis vs Vocabulary
"Vocabulary" traditionally implies lists of single words with definitions. "Lexis" signals a shift toward how words actually behave in use: their collocational profiles, grammatical patterns, register restrictions, and multi-word combinations. Michael Lewis's Lexical Approach (1993) made this distinction central to ELT methodology, arguing that "language consists of grammaticalized lexis, not lexicalized grammar."
The Mental Lexicon
The mental lexicon is the speaker's internal dictionary — a network of entries connected by form, meaning, collocation, and association. It is not a static list but a dynamic system:
- Words are stored with phonological, orthographic, syntactic, and semantic information
- Connections are strengthened through repeated encounters in context
- L2 lexical entries may be initially parasitic on L1 translations, gradually developing independent network connections (Jiang, 2000)
Nation's Framework
Paul Nation (2001, Learning Vocabulary in Another Language) provided the most influential framework for what it means to "know" a word, organized across three dimensions:
| Dimension | Receptive | Productive |
|---|---|---|
| Form | Recognise spoken/written form | Produce spoken/written form |
| Meaning | Retrieve meaning from form | Express meaning with correct form |
| Use | Recognise collocations, register, frequency | Produce natural collocations, appropriate register |
Each dimension has receptive and productive knowledge, yielding a rich, multi-layered picture. A learner may "know" a word receptively (recognise it in reading) long before they can use it productively with natural collocations.
Implications for Teaching
- Lexical units, not isolated words — teach make a decision, not just decision. Record vocabulary in chunks.
- Frequency-based selection — Nation's BNC/COCA word family lists and The Academic Word List provide principled vocabulary selection for different proficiency levels.
- Multiple encounters — Nation estimates 10-16 encounters for acquisition. Extensive reading and listening are the primary sources.
- Depth over breadth — knowing a word's collocational and grammatical behaviour (Colligation) matters as much as knowing its meaning.