Horse 1317 - You Say Potato I Say Potato

You say eether and I say eyether,
You say neether and I say nyther;
Eether, eyether, neether, nyther,
Let's call the whole thing off!
You like potato and I like potahto,
You like tomato and I like tomahto;
Potato, potahto, tomato, tomahto!
Let's call the whole thing off!- From "Let's Call the Whole Thing Off", by George and Ira Gershwin, 1937.
 
How does one pronounce the word "potato"? Actually the proper pronunciation was given in that three part documentary series "The Lord Of The Rings" by those two famed Theoretical Lexicographers, Sam Gamgee and Sméagol Gollum:
Sam: What we need is a few good taters.
Gollum: What's taters, precious? What's taters, eh?
Sam: Po-tay-toes! Boil 'em, mash 'em, stick 'em in a stew...

The key to pronouncing the word Potatoes lies in their history in relation to the UK.
Potatoes were brought back from the new world in 1592 by Walter Raleigh. Almost immediately a great craze followed and people started smoking them, building houses out of them and it wasn't long before people even started eating them.

Because of the fame of Raleigh who was knighted for his services and became Sir Walter Raleigh, potatoes themselves in England at least they were called "Raleighs" right up until 1835.
The Gaelic word for "Raleigh" or rather a "Rally" or journey is "Tayto", and this is still evident in the name of Ireland's biggest crisp manufacturer. http://www.taytocrisps.ie/

The word "Potato" derives from Edgar Allan Poe's poem "The Tayto" which was published in 1835 and was accused of being blasphemous and bawdy. Because of this the word changed to "Poetayto" and supplanted the orginal word almost entirely within 10 years. The modern spelling was finally codified with the arrival of the OED in 1895.

It would seem that the song by George and Ira Gershwin in 1937, either recalls this dispute of a pre to early Victorian era, or it could be dealing with a genuine mistake. Either way, it is an idea to "Call the Whole Thing Off" because convention after 117 holds that "Po-tay-toes" is the correct way to say the word.