The mean for receptive academic vocabulary size test was compared with 10.604 for productive vocabulary size test. This indicates that non-English major college students know more academic vocabulary receptively than they do productively. This is not surprising since much research on the comparison between receptive and productive vocabulary knowledge reveals that the development of productive vocabulary knowledge lags far behind that of receptive knowledge. The first step in learning a word is often to be able to recognize a word by its form and understand what it means. Then gradually,
with more practice of this word in reading, listening, writing, or some other activities, learners increase their knowledge of this word and learn to use the word productively in writing or speaking. Therefore, it is apparent that productive vocabulary knowledge builds on receptive knowledge.