I am not an Irish (or any kind of Celtic) speaker but orthography for those languages looks absolutely crazy to me. Both Welsh and Irish / Scottish Gaelic look like languages that might have benefited from their own alphabet, or at least the addition of some diacritical marks.

We also have no real idea how proto-Celtic or even Gaulish or early old Irish would have been pronounced. Only best guesses. We have inscriptions in e.g Gaulish from Roman times but they look to me suspiciously Latinized.

And then look at English.. it's a mismash of a bunch of different orthograpic conventions -- Anglo-Saxon, Norman French, Nordic, Latin, Greek... and makes no sense. Even us native speakers have no absolute certainty how to pronounce a word they've never seen before.