Although it is well‐known to most historical linguists that the comparative method could in principle be used to predict hitherto unobserved words in genetically related languages, the task of word prediction is rarely discussed in the linguistic literature. Here, we introduce 'reflex retrodiction' as a new task for historical linguistics and report on an ongoing experiment in which we use a computer‐assisted workflow to retrodict reflexes for so far unobserved words in eight varieties of Western Kho‐Bwa (a subgroup of Sino‐Tibetan). Since, at the time of writing this report, the experiment is still ongoing, we do not report concrete results, but instead provide an estimate of our expectations by testing the performance of the computational part of our workflow on existing language data. Our results suggest that reflex retrodiction has the potential of becoming a useful tool for historically oriented fieldwork.