French people can not use ´ for é ? Why not ` to manually input àè? The same for üöä with ¨. Maybe I lost something but we have 390 threads about keyboard and I am a little lost long time ago
Yes, that is possible, but it is less efficient since you have to press two keys for one letter. German keyboards have dedicated keys for üöä, French keyboards have dedicated keys for éèàç, and there's a good reason for that: in French, the letter é is more frequent than v, h, g, f, b, q, j, x, z, y, k, w (
source), so if all those letters have a dedicated key, then why not é?
In German it is a bit less important to have efficient access üäöß, since those are not
that frequent (but still more frequent than j, y, x, q;
source).
It's a bit arbitrary where to draw the line in these things. For example, in many languages, J is not that common (e.g. in English, J is used 10 times less frequently than the É in French), and since J is in a sense just an I with a hook-below diacritic, so you could also ask: can't English people just use
̡ + I for J ?
(to be clear: that was a joke, just to make my point)