This analysis of a corpus of 500 submorphemic typewriter slips in scientific reports demonstrates that slips of the key resemble slips of the pen, but differ from slips of the tongue, as speech errors arise under the influence of a fully deployed structural representation. The main features of key slips consist of a predominance of within-word slips, a high number of adjacent switches, a high rate of noncontextual slips, a heightened incidence of omissions, and an uncommonness of these slips in word edges.