How many words do you need to speak Arabic? An Arabic vocabulary size test

This study describes a vocabulary size test in Arabic used with 339 nativespeaking learners at school and university in Saudi Arabia. Native speakervocabulary size scores should provide targets for attainment for learners ofArabic, should inform the writers of course books and teaching materials,and the test itself should allow learners to monitor their progress towardsthe goal of fluency. Educated native speakers of Arabic possess arecognition vocabulary about 25,000 words, a total which is largecompared with equivalent test scores of native speakers of English. Theresults also suggest that acquisition increases in speed with age and thisis tentatively explained by the highly regular system of morphologicalderivation which Arabic uses and which, it is thought, is acquired inadolescence. This again appears different from English where the rate ofacquisition appears to decline with age. While the test appears reliableand valid, there are issues surrounding the definition of a word in Arabicand further research into how words are stored, retrieved and processedin Arabic is needed to inform the construction of further tests whichmight, it is thought, profitably use a more encompassing definition ofthe lemma as the basis for testing