> ASCII is enough to write English, or, at least, it used to be back when ASCII was a multi-byte encoding for Latin!

I know of both the over-strike method for traditional typewriters and extended ASCII. But I have no knowlede of a ASCII (extended or not) supporting every sign commonly used in English. Granted, it is not as significant as other languages missing whole letters, but signs like ”,“,—,–,’, which are often replaced with simpler ASCII alternative (",') or their combination (---,--).

Over-strike, from what I remember wasn’t implemented in any well-spread way with standalone ASCII, although I could be simply not aware of it. It gives us then a few more characters rarely used in English language in loanwords (née, naïve, façade).

Skipping diacritics with uppercase letters on displays with too little space happens with Polish language too, so I am aware of the practice.