When George Bernard Shaw said it was impossible for one Englishman to open his mouth without making another Englishman hate him, he was referring to the way tone of voice and accent communicated class distinctions. In "The Tailor Of Panama", John Le Carré describes a character as "like all Englishmen, branded on the tongue".
If you listen to as much speech radio as I do you're increasingly struck by the way that occupations seem to have developed accents and ways of speaking.
Top lawyers and civil servants still have the wintry drawl of the old-fashioned upper class. Scientists and naturalists, on the other hand, sound provincial and tentative. The latter group also seem to have a greater than usual tendency towards nervous tics.
Anyone who's made their living selling something to young people talks down their nose and avoids the consonants at the end of words. Actors talk quietly in an effort to muffle the natural richness of their voices. Rock stars never use sentences and will just reel out a ribbon of uninterrupted vocal noise in the key of "I" until you fade them out. Trade union leaders shout. Football managers seem to be the one professional group who cling fiercely to their regional accents as if their dressing room authority depended on it.
The majority of voices heard on the radio have been called upon to field some little local difficulty, whether it's penal policy or the flavour of yogurt, and they all tend to adopt the same non-specific, "I should point out" voice of redbrick reason. They have a rare skill for discussing a subject while killing further interest in it.