I used seán as a username once. I gave up after I realised it was fine on my own personal computer but once I jumped on to an azerty keyboard or something simpler tasks just became more difficult -- finding the letter with a fada just results in searching the charmap rather than keyboard.

You can have fadas in URLs e.g. seán.dev using a technique called Punycode.

Ogham is another Irish script and is vertical but unique in Unicode because its space charcter is a line - the only language to do so.

One of the few features I like on a Mac is that you can hold a key and it pops up a little menu which lets you chose many common variations of the letter without having your fingers do gymnastics on the keyboard.

This can be done without key combinations or a charmap: aáªàäâãåąæ

Is this possible on Windows or Linux? I constantly toggle between 3 keymaps.

That's clever, I like it. Not sure if something like this exists for Linux, but using compose keys is standard—e.g. to type å, I hit (in sequence) RightAlt, a, o.

I have síntí fada in my name too but I also frequently write in languages that use other accents so I have my keyboard mapping set up in software to type them easily. For example AltGr-a-' for á.

There's also significant value in everyone on Earth speaking the same language fluently.

Efficient communication is probably the most important factor in peace.