Many languages have developed a specialized tool for coding spatial background aspects of events: associated motion morphology (Guillaume 2016). This sparsely investigated verb inflection allows speakers to specify that the situation described by a verb takes place against the background of a motion event, as in ‘sing (while coming)’. Associated-motion systems typically include deictic information, and when verb inflection requires distinctions between motion in different directions, a thinking-for-speaking account (Slobin 2003) would predict cognitive consequences in the shape of heightened memory for direction. To evaluate this hypothesis, we compare encoding of and memory for direction in an endangered Otopamean language, Acazulco Otomí (Mexico). First, we examine diversity and frequency in the use of associated-motion inflection in pilgrim narratives. Then, we investigate the potential cognitive correlates with a psycholinguistic recognition-memory experiment measuring change-detection performance. Linguistic encoding of background direction was found to support memory for direction, but the sample size was small, and the experiment further indicated that both the associated-motion inflection and its corresponding attention patterns are in a process of dissolution. This echoes findings in Arrernte (Wilkins 2006) and Mojeño Trinitario (Rose 2015), and we discuss why associated motion might be an especially vulnerable category in language-endangerment contexts.