  Phonetic production bias is the external force most commonly invoked in
computational models of sound change, despite the fact that it is not
responsible for all, or even most, sound changes. Furthermore, the existence of
production bias alone cannot account for how changes do or do not propagate
throughout a speech community. While many other factors have been invoked by
(socio)phoneticians, including but not limited to contact (between
subpopulations) and differences in social evaluation (of variants, groups, or
individuals), these are not typically modeled in computational simulations of
sound change. In this paper, we consider whether production biases have a
unique dynamics in terms of how they impact the population-level spread of
change in a setting where agents learn from multiple teachers. We show that,
while the dynamics conditioned by production bias are not unique, it is not the
case that all perturbing forces have the same dynamics: in particular, if
social weight is a function of individual teachers and the correlation between
a teacher's social weight and the extent to which they realize a production
bias is weak, change is unlikely to propagate. Nevertheless, it remains the
case that changes initiated from different sources may display a similar
dynamics. A more nuanced understanding of how population structure interacts
with individual biases can thus provide a (partial) solution to the
`non-phonologization problem'.
