When I used to present programmes on English usage on Radio 4, people would write in and complain about the pronunciations they didn’t like. In their hundreds. (Nobody ever wrote in to praise the pronunciations they did like.) It was the extreme nature of the language that always struck me. Listeners didn’t just say they “disliked” something. They used the most emotive words they could think of. They were “horrified”, “appalled”, “dumbfounded”, “aghast”, “outraged”, when they heard something they didn’t like.

Why do people get especially passionate about pronunciation, using language that we might think more appropriate as a reaction to a terrorist attack than to an intruded “r” (as in “law(r) and order”)? One reason is that pronunciation isn’t like the other areas of speech which generate complaints, such as vocabulary and grammar. You may not like the way people use a particular word, such as disinterested, but you’re not going to meet that problem frequently. Similarly, if you don’t like split infinitives, you won’t hear one very often. But every word has to be pronounced, so if you don’t like the sound of an accent, or the way someone drops consonants, stresses words, or intones a sentence with a rising inflection, there’s no escape. Pronunciation is always there, in your ears.

Pronunciation gives us a clue about a speaker’s ethnic group and social class ... always a potentially sensitive subject

Another reason is that pronunciation is not only the foundation of clarity and intelligibility, it also expresses identity. When we hear someone speak our language, we not only recognise the words that are said, we recognise who is saying them. It is pronunciation, more than anything else, that makes someone sound British, American or Indian; from Liverpool, Newcastle or London. It is pronunciation – again, more than anything else – that gives us a clue about a speaker’s ethnic group, social class, education or occupation. So it’s always a potentially sensitive subject.

Identity is primary. My BBC critics were not usually suggesting listeners couldn’t understand what speakers were saying; they were complaining about the way they were saying it. Some criticisms were aesthetic: a pronunciation might be called “ugly” or “sloppy”. Some expressed dislike of an accent. Indeed there was the occasional comment about unintelligibility, such as when presenters emphasised a word ambiguously or dropped their voice at a critical moment. But typically, when people talked about unacceptable pronunciation, they weren’t thinking of the content but the delivery.

It’s the same today. Sometimes the criticisms reflect a state of affairs that everyone would agree with, because it’s based on objective fact: if a voice is genuinely inaudible, or someone speaks so quickly that it’s impossible to follow (such as over a public-address system), there is nothing to dispute. But most pronunciation complaints aren’t like that: they are matters of taste, where the viewpoints reflect differing perceptions as to what is appropriate, pleasing or correct – auditory beauty, lying in the ear of the listener.

What voices will we ascribe to our robots? Photograph: Aflo / Barcroft Images

I wrote Sounds Appealing to introduce a broader perspective – not to ignore the problems, but to put them in perspective, as just a tiny part of the amazing range, intricacy, power and beauty of the English sound system. Phonetics opens our ears to a fascinating world. Why do we favour certain sounds when we write poetry, tell nursery rhymes, devise clever character names or swear? There are powerful and productive phonetic patterns underlying “Fair is foul, and foul is fair”, “Hickory Dickory Dock”, Augustus Gloop, and feck. They need to be appreciated. Or again: what happens to our speech in unusual speech situations, such as when we try to talk with our mouth filled or covered? The occasions go well beyond eating – think dentists and Darth Vader.

Then there’s the time dimension – the inexorable process of pronunciation change. How do we discover the speech sounds of the past? We can hear Florence Nightingale, in an early recording, read Isaac Newton’s notes describing his accent, and listen to the BBC archive, but how do we reconstruct Shakespeare, Chaucer or Beowulf? And what about the future? Big pronunciation issues face us in this century – not least, what voices will we give our computers and robots?

If we spend all our auditory energy paying attention just to the things we don’t like, we are missing out on so much. All the moans – about h-dropping, r-intruding and the like – amount to less than 5% of everything that goes on when we pronounce our words and sentences. So my phonetic manifesto for the 21st century – and the theme of my book – is: it’s time to focus on the other 95%. As Anthony Burgess once said (in A Mouthful of Air): “Phonetics, phonetics, and again phonetics. There cannot be too much phonetics.”

Sounds Appealing: The Passionate Story of English Pronunciation is published by Profile.