Yellow dead keys, how to disable

According to this article: macOS Sierra: Enter characters with accent marks i am able to type certain special characters using so-called "dead keys":

"If you often type characters with diacritic marks, it may be quicker to use dead keys (a modifier key pressed with another key in order to enter a letter with a diacritic mark). For example, to enter â using the ABC keyboard layout, you press Option-i together, then type a."

However, for some strange reason if i press those keys (~,",^,', `) where they normally are (without Option or anything) on QWERTY US layout, i get the identical effect to described above. This is very annoying because when you want to use the characters as they are you have to additionally press Space to "exit" the dead key mode (which is simply frustrating in case of ", double quote, that is used rather frequently).

I only have "US International PC" and "Russian" layouts and no "funny" languages that even have these characters. So far i have only found one post about it for Snow Leopard: Double quote "special character" mode, which is N/A to Sierra. I have found no setting/option in OSX Preferences for this behaviour (or was unable to identify one correctly anyway).

Apple support, how the **** do i turn this off?