in a communication between individuals having different levels of skill in a language , communication by the more skilled individual is controlled so as to keep it at a level understandable by the lesser skilled individual . for example , a native speaker &# 39 ; s communication with a student learning his language is monitored by an interface and compared with a stored model representing the student &# 39 ; s knowledge and ability in the language . should the native speaker communicate in a way that would not be understood by the student , for example , by using vocabulary or a sentence structure beyond the student &# 39 ; s ability , the interface will notify the native speaker . the interface might then suggest an alternate word or sentence structure to the native speaker , inviting him to use the alternate communication . the native speaker can then substitute and send the alternate communication .