How do you pronounce an initialism like HTML?

I was taught English in public Australian schools of the 1970s. So I was taught aitch rather than haitch. Which means I pronounce ‘HTML’ with an initial vowel sound and I write ‘an HTML page.’

If I’d gone to a private Irish Catholic school, however, I would have been taught haitch and would, naturally enough, think ‘a HTML page’ is correct.

More generally, haitch is standard in Hiberno-English and is a way for disputing Protestant and Catholic Northern Irelanders to distinguish themselves from each other.

So, if I insist on ‘an HTML page’ I’m telling 4.5 million English speakers their way of writing and speaking is wrong, or non-standard at the very least. And I can’t reveal accent by writing ‘an ’TML page’ because it’s a technical document, not a novel.

Seriously though, how many Irish Catholics are going to tear up their Linux manuals in disgust after discovering a pernicious “an” embedded in the text? It’s nothing personal. Technical writers are just following a style guide. Some tech writers will go with “a html” because they look at the expanded form of the initialism. So “a Hypertext Markup Language Page” would be written as “a html”. Does that mean everybody who pronounces “h” as “‘aitch” (which is the majority of the English-speaking world) should label these writers as hate-mongering, prejudiced Irish Catholics?

It all comes down to schisms in pronunciation. Yet, in today’s globalized world, there isn’t much room to argue with the majority.