According to this abstract, published in 2007, "the half-life of an irregular verb scales as the square root of its usage frequency: a verb that is 100 times less frequent regularizes 10 times as fast." The data that supports this study comes from 177 English irregular verbs, traced over a time span of 1200 years of evolution.
How much is known about verb regularization rates in other languages? Does the data collected so far, for the studied languages, show the same correlation?