The uvular /r/ has spread into many languages of Europe. At one time, all European languages had an /r/ that was pronounced as an apical trill or flap. This is not surprising because the apical trill and flap are the most common /r/ sounds. However, the /r/ of Parisian French changed from an apical trill to a uvular. This pronunciation spread not only into French but also to other languages. As a result, it is now standard not only in French but also in German and Danish. It is also common in many varieties of Swedish, Norwegian and Dutch.
The change in the pronunciation of the French /r/ may have taken place in the 1600's. In an area of Sweden located between Stockholm and the southernmost part of the country, the uvular trill has replaced the alveolar trill in certain contexts but not in others. The alveolar trill occurs word-finally and the uvular trill occurs word-initially. This is the opposite of southern Germany and Austria where many speakers have a word-initial alveolar trill and a word-final uvular fricative.
In the Portuguese of Lisbon, the syllable-initial /r/ is uvular. It is a tap when it occurs intervocalically but the orthographic "rr", a multiple trill in Spanish, is a uvular trill in Lisbon. This uvular pronunciation does not occur in the rest of Portugal. As it only occurs in the area around Lisbon, it may be termed an urban phenomenon.
The adoption of the uvular /r/ is more common in urban centres than in rural ones. It appears that innovations tend to spread in urban centres. Rural areas, on the other hand, tend to resist them. The diffusion of the uvular /r/ which originated in Parisian French is one such example.