… yet you have contracted «artificial intelligence» to «AI», have not you?

The case for abbreviated keywords will always exist as some will prefer contractions whereas some will have a preference for fully spelled out words.

At the opposite side of the spectrum there C / C++ that use neither for functions and procedures but «printf» and «strcpy» – as you have rightfully pointed out which ADA, COBOL and Objective C contrast with

  ADA: «Is_Valid_User_Access_Level_For_Requested_Operation», «Convert_String_To_Standardised_Date_Format»

  COBOL: «PERFORM Calculate-Totals VARYING Index FROM 1 BY 1 UNTIL Index > Max-Index»

  Objective C: «URLSession: dataTask: didReceiveResponse: completionHandler:»

Well the threshold I would like to use is "abbreviations that are easily understood outside of coding jargon are acceptable". You don't have to be a specialist in any specific language to understand "AI" in the wild, or "NASA" or even the names of languagues such as COBOL.

But if outside of the context of coding you just say "strcpy" or "writeln" at somebody they're not going to immediately understand. As a result, even coders with tired brains or who are switching between languages a lot will also get hung up at inconvenient times.