I talk about “r” a lot here*. Seriously, if you take a look at this site’s analytics, you’ll find that the Google query that brings the most traffic is simply “r.” The consonant is one of the most important ways by which we distinguish English accents, so this shouldn’t be surprising.
Anyway, I was up in Montreal a few weeks back, where I got a great opportunity to listen to one of North America’s great non-English dialects. One of the things I’d long heard about Montreal French was that, unlike its Parisian cousin, it once featured a trilled [r] (similar to Spanish or Italian). I can’t say I heard a single instance of this on Montreal’s streets though; it seems pretty clear that, as of 2013, the uvular /r/ (i.e. [ʁ], [ʀ], or [χ]) rules the day. /R/, you see, isn’t just a large dialect marker in English; it’s a common marker in numerous Indo-European languages.
Montreal French, like American English, seemed to have undergone a transition after World War II when it comes to rhotics. Here’s a brief summary from Nagy, Moisset, and Sankoff’s On the acquisition of variable phonology in L2:
Before about 1950, the Montréal dialect had tongue-tip [r], r roulé, whereas Québec City and the rest of Eastern Québec had uvular [R], r grasseillé (Vinay 1950). As of the 1950s, Montrealers began to change to [R], such that by 1971, most speakers under 25 had uvular [R], not apical [r].
Just as New Englanders, New Yorkers, and American Southerns began to tack /r/ at the end of words where it was once non-existent, Montrealers began to shift from their traditional, regionally specific [r] to a more “Parisian” variant.
The Montreal French shift rather reminds me of another “r” divide: Puerto Rican Spanish‘s variation between the alveolar and velar /r/. Like /r/ in other languages, this correlates with sociological factors such as age. For instance, Jonathan Carl Holmquist conducted a study based on recordings made in the mid-1990s in which he found that rates of /r/ allophones differed between generations. In the town where his study was focused, speakers over 65 used [x] 90% of the time (the consonant more commonly used in other dialects of Spanish for “José”) Speakers under the age of 39, however, used this marked allophone only 28% of the time. (Again this seems to align roughly with the period after World War II.)
These are but two examples, of course. /R/ divides Brazilian from European Portuguese (along with dialects within those countries themselves), distinguishes various dialects of Latin American Spanish (beyond PR mentioned above), and separates dialects of German, Dutch, Norwegian, and Swedish. Whether because /r/ is a consonant acquired relatively late in a child’s development (at least in English), or because of larger historical trends (the spread of uvular /r/ across several countries in Western Europe), it’s a salient marker in numerous parts of Europe and the Americas.
So given this site’s intense /r/ focus, it’s worth noting that English is not unique in this regard. It’s part of a larger phenomenon in which /r/ is an particularly unstable consonant, capable of changing radically in a generation. And as my Montreal example showed, you don’t have to travel very hard to find non-English examples.