Previous studies on the diachrony of wh-interrogation in Brazilian Portuguese have observed a replacement process of ex-situ-wh interrogatives by cleft-wh and in-situ-wh interrogatives in the twentieth century. The present study analyzes almost 19,000 wh-interrogatives from a corpus of theater plays dated between 1800 and 2016, demonstrating that not all of these frequency changes constitute actual change. The increase in the usage frequency of several types of wh-interrogatives is partially or entirely due to changes in the degree of orality of theater plays, or changes in word order. Moreover, only some of these changes can be characterized as changes from below, that is, changes in which high-orality texts are affected by the frequency increase first. This notion is also relevant for functional change in wh-interrogatives. Over time, the use of cleft-wh and in-situ-wh interrogatives spread from contexts in which the proposition is highly accessible to low-accessibility contexts. For cleft-wh, this change is moderated by orality, again indicating change from below.