@pmcg @mathewi
1. Dead keys were invented on mechanical typewriters so I'm hoping nobody granted Apple a patent on it.

2. I have an iPad with Apple keyboard cover and I can't get dead key to work on it, at least not whilst English is the default language. It uses a more cumbersome system. Apple aren't infalible.

3. You can get dead key mechanics on Windows for various diacritics. It's been there since forever. Set your keyboard language to "United States (International)" and that's it.