Despite 14 people following my link, everyone’s still confused.
It’s an agreed callsign, it doesn’t matter what it is. I mean, Speedbird isn’t the same as British Airways but no-one finds that strange.
Edit: after posting this, it occurred to me that it’s like that so it sounds the same as possible regardless of the nationality or accent of the person saying it.
British Airways inherited the Speedbird callsign from BOAC, who they merged with in 1974. BOAC’s logo included a stylised bird:
I also have this “problem”. My language interface is german and azure cloud translate “Air France” to “AirFrans”. Azure Cloud also writes german ATC in subtitles and say it with an English pronunciation.
This topic is like an echo chamber… where no one is reading any of the actual helpful responses.
The quote below is from https://en.wikipedia.org/wiki/Airline_codes:
The (ICAO) callsign should be easily and phonetically pronounceable in at least English, the international language of aviation. For example, Air France callsign is “Airfrans”; ‘frans’ is the phonetic spelling of ‘France’.
it’s surreal!
It can’t be so easy!
Frankly speaking I did not know Speedbird too but is sounds more reasonable so I did not realize it. But Airfrans sounds strange, that’s why I got confused.
And US airways is “cactus”, aïe aïe aïe 
MODERATOR EDIT:
Wasn’t their operation discontinued many years ago?
Wurde deren Betrieb nicht vor vielen Jahren eingestellt?
Sorry. Was in a german Forum at the same moment.
There are a number of strange callsigns used by airlines.
BA - Speedbird
South Africa - Sprinfbok
Air Lingus - Shamrock
Conquest Air - Chickpea
Canadian North - Arctic
Just to name a few…
