Discussed briefly by the author are some of the "most immediately relevant" implications for TESOL which arise from research studies in dialectology. One phenomenon, which until recently has received little attention, is that of "receptive bi-dialectalism" or "bilingualism." One of the earliest observations of this phenomenon is a passage taken from the writing of Daniel Defoe in 1724. An individual, presented with a stimulus in one dialect and asked to repeat it, will respond by producing the form that is native to his own dialect rather than the form which he has heard (or read). The author feels that such evidence should give us pause in attempts to judge a child's linguistic competence solely or even largely on the basis of his production; rather we should begin by attempting to assess the child's receptive competence as the basis from which to proceed in determining appropriate instructional procedures. If the child has an already well-developed receptive knowledge of a more formal or "mainstream" dialect of the language, much of the instructional task can be seen as guiding him toward an automatic productive control of the "mainstream" dialect. Implicit in this approach is the idea that only positive stimuli and motivations will be supplied to lead him to develop and practice this control, and that no negative values or stigmas will be applied to his use of his native linguistic forms. (AMM)