You should have left out the first sentence! Someone once sent me a link to a tooth-grindingly annoying performance by an English "comedian", where he expressed

You should have left out the first sentence! Someone once sent me a link to a tooth-grindingly annoying performance by an English "comedian", where he expressed irritation and disbelief at what he saw as a preposterous disconnect between the spelling of indigenous Irish names and the way they are pronounced. As if the Irish language was really merely a dialect of English, and we're all just being awkward over here. Someone who knows English but not Irish will have no idea how to pronounce "Niamh", because it's not a word from the English language. As you say, it's an Irish name that follows Irish orthography.