The presence or absence of non-prevocalic /r/, also known as rhoticity, has been frequently examined in studies of language variation and change with some varieties gaining rhoticity e.g., New England (Nagy and Irwin 2010), New York (Becker 2009) and the Southern United States (e.g., Feagin 1990) and others losing it e.g., southwest England. However, there have been few attempts to look at the linguistic constraints on non-prevocalic /r/ use cross-dialectally. This paper attempts to do this, introducing new data from the southwest of England, to see to what extent the linguistic constraints on /r/ use can be said to be universal and to see whether they are the same in varieties gaining and losing rhoticity. Do those dialects losing rhoticity follow the same linguistic path as those gaining it? If so, are the linguistic constraints which most strongly favour /r/-loss in southwest England the same ones that promote the acquisition of /r/ in the US? Taking Nagy and Irwin (2010), as a point of comparison this paper examines the paths of change and finds that there are commonalities in the environments most promoting of /r/ regardless of whether the variety is losing or gaining rhoticity. This paper also shows the steep decline in non-prevocalic /r/ use in both real and apparent time and provides a multivariate analysis of the linguistics constraints of this change.