Drawing on the dynamics among manuscript texts and textual criticism, this essay addresses everyday medieval English (as opposed to literary English), both as a definable variety and as a theoretical construct in historical linguistics. It focuses in particular on the material effects that written texts and printed editions have on how we perceive Old and Middle English in general, as well as on the theoretical implications of trying to understand what living, spoken languages were on the basis of the written remains of languages now extinct. In many cases, the issue is not simply whether we can or cannot surmise that some linguistic feature was part of the general repertoire. It is whether we have any basis at all for discriminating the unrehearsed from the stylized and for generalizing from that discrimination to some understanding of medieval English in general. Rather than simply affirm what we already know, the extant record might sometimes remind us of things we do not and cannot know.