Create /usr/share/X11/xkb/symbols/us_de with the following content:

partial default alphanumeric_keys
xkb_symbols "basic" {
    name[Group1]= "US/ASCII";
    include "us"

    key <AD03> {[e,          E,           eacute,         Eacute]};
    key <AD07> {[u,          U,           udiaeresis,     Udiaeresis]};
    key <AD09> {[o,          O,           odiaeresis,     Odiaeresis]};
    key <AC01> {[a,          A,           adiaeresis,     Adiaeresis]};
    key <AC02> {[s,          S,           ssharp,         ssharp]};
    key <AE05> {[NoSymbol, NoSymbol,      EuroSign]};

    key <RALT> {type[Group1]="TWO_LEVEL",
                [ISO_Level3_Shift, ISO_Level3_Shift]};

    modifier_map Mod5   {<RALT>};
};

And create /etc/X11/xorg.conf.d/00-keyboard.conf with the following content:

Section "InputClass"
        Identifier "system-keyboard"
        MatchIsKeyboard "on"
        Option "XkbLayout" "us_de"
EndSection

Thanks to elastocloud.org where I found this solution.

syndaemon -d -i 0.25 -K -R

Found at: https://www.condensedmatters.org/2014/02/turn-off-touchpad-while-typing-on-linux/