Examples and Observations:
- "A passive vocabulary . . . includes the words stored in verbal memory that people partially 'understand,' but not well enough for active use. These are words that people meet less often and they may be low frequency words in the language as a whole. In other words, activating them takes longer and it demands greater stimulus than most textual contexts provide. Words stop being passive if people are regularly contracting relations that activate them, since this lowers the amount of stimulus needed to put them to use. A facility in using the words develops. Again constraints of another kind in the extralinguistic context may also restrict the active use of some words. This can happen even when words are available for active use in principle, such as cultural taboo words that most people know but rarely use outside certain settings."
(David Corson, Using English Words. Kluwer Academic Publishers, 1995)
- "Media saturation may . . . provide what Dennis Baron called a 'passive lingua franca.' We all understand what we hear on the radio or see on TV, giving us a passive vocabulary, but that doesn't mean that we use that vocabulary actively in writing or speaking."
(Robert MacNeil et al., Do You Speak American? Random House, 2005)
- "Take your dictionary and peruse 1 per cent of its pages, i.e. 20 pages of a 2,000-page dictionary, or every hundreth page (you need to take a range of letters of the alphabet). Note down how many words: (a) you are confident that you would regularly use; (b) you would recognize and understand if you read or heard them. Be brutally honest with yourself! Then multiply your totals by 100, to give a first approximation of your likely active and passive vocabularies."
(Howard Jackson, Grammar and Vocabulary: A Resource Book for Students. Routledge, 2002)