Oxford University Press (Oxford Dictionaries), in remembering April 19 as the anniversary of the first airing of The Simpsons on American television (the first episode appeared in 1989), does some linguistics considerations on their contribution to the common speech. Three quotations are on The Oxford Dictionary of Modern Quotations:
‘D’oh’ , Homer’s main expression, which is in the official on line version of the Oxford English Dictionary (the earliest citation for doh dates from a 1945 BBC radio script for the show ‘It’s That Man Again’ and Its inclusion in The Simpsons seems to be due to voice actor Dan Castellaneta).
‘¡Ay caramba, don’t have a cow!’ (by Bart, although it had already been used in 1980s film ‘Sixteen Candles or Scooby Doo’; used as an expression of surprise and seemingly originates from the nickname given to the 18th-century Spanish singer Maria Antonia Fernandez)(in Italy Bart says ‘Ciucciati il calzino’ and Bender, another Matt Groening’s creation, “mmm…shorts”);
‘Me fail English? That’s “unpossible”!’ (by thedopey policeman’s son Ralph Wiggum; it is interesting to note that “umpossible” remount s to 1362 and it was a commonly used word between c.1400-1660) (in Italy Winchester speaks in Neapolitan dialect);
Definitely, Simpson family made their precise mark on the English language.