To address this problem, Hall and Klein (2010) propose an iterative bipartite matching scheme where one language is held out from the others, and then words are assigned to the remaining groups to maximize the probability of the attachment.
for some language and fixed assignments π − for the other languages, they seek an assignment π that maximizes: Unfortunately, while this approach was effective with only a few languages (they tested on three), this algorithm cannot scale to the eighteen languages in Formosan, let alone the hundreds of languages in Oceanic.