A dogwhistle is a communicative act intended to broadcast a message only understood by a select in-group while going unnoticed by others (out-group). We illustrate that political dogwhistle behavior in a more radical community precedes the occurrence of the dogwhistles in a less radical community, but the reverse does not hold. We study two Swedish online communities – Flashback and Familjeliv – which both contain discussions of life and society, with the former having a stronger anti-immigrant subtext. Expressions associated with dogwhistles are substantially more frequent in Flashback than in Familjeliv. We analyze the time series of changes in intensity of three dogwhistle expressions (DWEs), i.e., the strength of association of a DWE and its in-group meaning modeled by Swedish Sentence-BERT, and model the dynamic temporal relationship of intensity in the two communities for the three DWEs using Vector Autoregression (VAR). We show that changes in intensity in Familjeliv are explained by the changes of intensity observed at previous lags in Flashback but not the other way around. This suggests a direction of travel for dogwhistles associated with radical ideologies to less radical contexts.

We test whether the development of political dogwhistles can be observed using language change measures; specifically, does the development of a “hidden” message in a dogwhistle show up as differences in semantic change between communities over time? We take Swedish-language dogwhistles related to the on-going immigration debate and measure differences over time in their rate of semantic change between two Swedish-language community forums, Flashback and Familjeliv, the former representing an in-group for understanding the “hidden” meaning of the dogwhistles. We find that multiple measures are sensitive enough to detect differences over time, in that the meaning changes in Flashback over the relevant time period but not in Familjeliv. We also examine the sensitivity of multiple modeling approaches to semantic change in the matter of community divergence.