... Over many years we have come to realize how deeply exhausting it is to actually say the entire word fifteen...
- Darius Marder
( Source: NYTimes.com | Straight Sets: Quirks of the Game: How Tennis Got Its Scoring System )
It sounds rather silly but can you imagine how much time would be saved by halving the number of syllables in a word that is repeated so often?
That's probably why the technology industry uses so many acronyms - it's more efficient to say "SQL" than "Structured Query Language". Can you imagine saying "Structured Query Language" if you were a developer every time it was needed? OMG.
Also, still in sports and along the same efficiency-line-of-thinking, aren't players in the NBA encouraged to use numbers below six when they are double-digits, mainly for referees who have to reference a player for a foul? They just held up two fingers on one hand and three fingers on the other to call Michael Jordan out.
It all sounds silly, unless you are the one that is repeating the action many times.