When a game is tied at 15 or 30 the French tennis announcers say something that sounds to me like "quinze un " (resp. "trente un") or maybe "quinze an" . "Quinze" is only said once, no "quinze quinze" or "quinze partout'. My best guess is that the final vowel is emphasized and they are saying 'quinz-E' ? Does someone know ?
I first believed it was trente à, and short for trente à trente. But it's actually written trente-A in official tennis procedures :
It might come from the English “thirty all”.
Tennis scoring is very peculiar. In table tennis or in basically every other sport we would use a different and much more logical shortcut: trente partout (assuming such a score did exist).