In all aspects of culture, the leaders who introduce innovations, whether consciously or not, are gradually followed by the rest of the population who wish to emulate them. This is most obvious in clothes, where before the instant communications of the present day, it was well-known that the fashions of London and Paris slowly percolated out into the provinces, first to other big cities and centres of population, and eventually to the country districts. Until the 19th century, this could take decades.
In language, the prestige forms have always tended to be those used by the rulers and other respected people. ‘Standard’ Old English, for instance, i.e. the form of that language mainly studied today, was that of Wessex, where King Alfred’s court was highly respected and dominated England outside the Danelaw. By the time of Middle English, the centre of influence had moved to London, and the standard dialect, from which Modern English developed, was that of the south east midlands. When the BBC was set up, RP was chosen as the accent to be used by most of its announcers as it was judged to have more prestige than any other.
For particular aspects of West European culture, however, other languages have dominated. Classical music, for instance, was largely codified in Italy, and many of our musical terms are borrowed from Italian: sonata, cantata, symphony, opera, orchestra, piano, violin, timpani, tuba, crescendo, allegro con fuoco. The related art of dance, however, was very important at the court of Louis XIV at Versailles, and most of our ballet terms are French: pas de deux, adage, ballet, pirouette. These terms are common to most European languages. In the late 19th Century, English sports were exported. and the associated words were borrowed by other languages, sometimes as a direct translation (German Fussball) or by a re-spelling (Spanish fútbol) or not even that (French football).
In the present day, the centre of Western culture is the US, and the international terms are borrowed from its form of English for computing and ‘popular’ culture, such as pop and rock music, and film. Until the beginning of the 20th century, it could be said that the US, for all its larger – and growing – population than the UK, was part of the periphery of the language, retaining many features that had been changed in the British Isles. Now there can be no doubt that Britain is part of the periphery, and the US the centre. Individual changes include trivial ones such as the pronunciation of Vietnam as /viːetˈnɑːm/, which started to replace /viːetˈnæm/ only after Hollywood started to make films about the conflict,or the phrase train station in place of the traditional railway station (mostly in my unscientifically tested view used by people born after about 1965). Most obviously is the tendency for rock singers to use American-type accents rather than English. Some people might attribute this last to a failure in self confidence on the part of British rock musicians – even The Beatles used American accents on their early releases, before they started to celebrate their Liverpool roots – but I think it is simply another example of the natural desire of people to emulate what they see as the best in their field.