Tomato, tomahto is a popular saying, comparing the two possible pronunciations of the word tomato, the lifeblood of Italian cuisine and ketchup sauce.
The expression itself is used to dismiss unimportant arguments about minute details.
The origin of the difference in pronunciation of the tomato plant lies in The Great Vowel Shift, which occurred in the English language in the 15th and 16th centuries – the time, when the plant was introduced to Europe by the Spaniards.
Initially, the tomato plant was pronounced tomahto by English speakers of the early 16th century, however by the time of Shakespeare, it started taking on a short ae sound, which resulted in a now unfamiliar pronunciation, with an “a” sound similar to that found in words like cat, and which evolved in the Americas to the widely known tomayto pronunciation.
Meanwhile in the 18th century, the short “a” sound in the southern regions of the British Isles started morphing into a long, broad “a” sound, which resulted in the birth of the currently known tomahto pronunciation, associated with posh Brits and Bostoners.
“Tomato, tomahto” became a colloquial expression, highlighting the senselessness of arguing about minute details during the 20th century.
Since the introduction of the internet, the phenomenon grew even more significantly, appearing in countless sources of contexts, including a 2013 YouTube video, uploaded by Simple English Videos on August 30th, under the title Tomahto – Tomayto: British and American Pronunciation Song.
The phrase was first defined on Urban Dictionary on February 21st, 2019.