Lexical Coverage in L1 and L2 Listening Comprehension: The Same or Different from Reading Comprehension?

Most research on L2 reading comprehension has indicated that 98 per cent lexical coverage provides adequate comprehension of written text. This figure has been transferred to listening comprehension and has been used to set vocabulary size targets for L2 learners. This study directly investigates coverage in regard to listening comprehension, to determine whether such transfer is reasonable. The coverage of four spoken informal narrative passages was manipulated, and participants' (36 native and 40 non-native speakers) listening comprehension of factual information was measured. Results showed that most native and non-native participants could adequately comprehend the spoken texts with only 90 per cent coverage, although the non-natives showed considerable variation at this level. At 95 per cent coverage, non-native participants also demonstrated relatively good comprehension, but with much less variation. Based on a 95 per cent coverage figure, language users would need to know between 2,000 and 3,000 word families for adequate listening comprehension, compared with Nation's (2006) calculation of 6,000-7,000 families based on a 98 per cent figure.