  The processes leading to change in languages are manifold. In order to reduce
ambiguity in the transmission of information, agreement on a set of conventions
for recurring problems is favored. In addition to that, speakers tend to use
particular linguistic variants associated with the social groups they identify
with. The influence of other groups propagating across the speech community as
new variant forms sustains the competition between linguistic variants. With
the utterance selection model, an evolutionary description of language change,
Baxter et al. [Phys. Rev. E 73, 046118 (2006)] have provided a mathematical
formulation of the interactions inside a group of speakers, exploring the
mechanisms that lead to or inhibit the fixation of linguistic variants. In this
paper, we take the utterance selection model one step further by describing a
speech community consisting of multiple interacting groups. Tuning the
interaction strength between groups allows us to gain deeper understanding
about the way in which linguistic variants propagate and how their distribution
depends on the group partitioning. Both for the group size and the number of
groups we find scaling behaviors with two asymptotic regimes. If groups are
strongly connected, the dynamics is that of the standard utterance selection
model, whereas if their coupling is weak, the magnitude of the latter along
with the system size governs the way consensus is reached. Furthermore, we find
that a high influence of the interlocutor on a speaker's utterances can act as
a counterweight to group segregation.
