Whenever a teacher orally explains something to a class or a pupil, wheneverpupils talk to each other or hear speech, the information presented is transient. Byits very nature, all speech is transient. Unless it is recorded, any spoken informationdisappears. If it is important information for the learner, then the learner must tryto remember it. Remembering verbal information often can be more easily achievedif it is written down. Writing was invented primarily to turn transient oral informa-tion into a permanent form. In the absence of a permanent written record, thelearner may need to use a mental rehearsal strategy to keep information alive inworking memory before it dissipates. The more information there is to learn, themore difficult it becomes to remember, unless it is written down, or students haveadditional access to a permanent record. Furthermore, if spoken informationrequires complex processing, then the demands made on working memory becomeeven more intrusive. For example, if a teacher explains a point using several spokensentences, each containing information that must be integrated in order to under-stand the general gist, the demands made on working memory may be excessive.Information from one sentence may need to be held in working memory whileinformation from another sentence is integrated with it. From this perspective, suchinformation will create a heavy cognitive load. Accordingly, all spoken informationhas the potential to interfere with learning unless it is broken down into manageableproportions or supported by external offloads such as written notes.