How to pronounce data

Short answer: say DAY-tuh (/ˈdeɪtə/), with the "ay" of day. Merriam-Webster, American Heritage, Dictionary.com, Cambridge, Oxford Learner's Dictionaries and Collins all list it first, and the last three do so for British English too. American dictionaries also list DAT-uh (/ˈdætə/), with the "a" of cat, and Oxford and Collins give British English a second option, DAH-tuh (/ˈdɑːtə/). All three are correct.

Listen

Both American clips are by one speaker, so you can compare the vowels. We found no labeled British clip; for British DAY-tuh, Cambridge shows a crisp T instead of the quick American one.

Is it DAY-tuh, DAT-uh or DAH-tuh?

All three are in the dictionaries:

Cambridge gives British speakers only DAY-tuh. Wiktionary, which cites no source here, calls DAH-tuh the usual form in Australia, New Zealand and South Africa.

Polls point the same way. In a 1988 postal poll of 275 British speakers for the phonetician John Wells's Longman Pronunciation Dictionary, 92% preferred DAY-tuh, 6% DAH-tuh and 2% DAT-uh. In a survey of 395 Americans by his student Yuko Shitara, published in 1993, 64% chose DAY-tuh, 35% DAT-uh and 1% DAH-tuh, and DAT-uh was linked to younger respondents. Both panels included many language professionals and students, so neither was a random sample.

One famous DAY-tuh is the android Data on Star Trek: The Next Generation. In "The Child", the 1988 season 2 opener, Dr. Katherine Pulaski calls him DAT-uh (Memory Alpha's spelling), and he corrects her. When she asks what the difference is, he answers: "One is my name. The other is not."

So which should you use? DAY-tuh is the safe choice anywhere: it's first in all six dictionaries in the table and won both polls. DAT-uh is fine in American English, and DAH-tuh in British English. Just be consistent.

Why is data pronounced in different ways?

Data is the plural of Latin datum, "something given", from dare, "to give". Merriam-Webster dates the first known use in English to 1630. It entered English as a term in philosophy, for a fact given or granted, and the computer sense is recorded by 1946. Date, as in the day on a letter, comes from the same Latin verb.

In Latin, the A was short, closer to "ah". But English traditionally read Latin with English vowels: a stressed vowel before a single consonant in the next-to-last syllable became "long", whatever its length in Latin. That turned da- into "day". Later, some speakers shortened it to the "a" of cat. Wikipedia's article on the traditional English pronunciation of Latin uses data as its example, and Wiktionary calls DAT-uh a spelling pronunciation. DAH-tuh, Wiktionary says, adapts the Latin sound.

How to say data step by step

1. Pick your vowel: "ay" as in day, "a" as in cat or "ah" as in father.
2. Stress the first syllable: every dictionary above marks it.
3. Say the T your way: in American English, the T between vowels is a quick tap, close to a D, so DAY-tuh sounds almost like "DAY-duh". In British English, it's a crisp T.
4. End with a weak "uh": all six dictionaries in the table give a schwa (/ə/) here, not a full "ah".

In Italian, Portuguese and Polish (and, less often, Spanish), data means "date" and starts with "ah". If that's your first language, you can keep the "ah" (DAH-tuh), but reduce the ending to "uh".

Practice in a sentence

• The data shows a clear trend.
• Our data team meets every Monday.
• DAY-tuh, DAT-uh or DAH-tuh: the numbers stay the same.

Then try words with the same vowel choice. American pronunciations, from the Cambridge Dictionary:

Americans and Britons also split on either, route and aunt, and niche is another word with more than one correct version.

What does data mean?

Data means facts and figures gathered to be examined and used for decisions. It also means information in electronic form that a computer can store and process. Cambridge and Merriam-Webster give both senses. Grammar is a separate debate: Dictionary.com says data is usually plural in scientific and academic writing (the data are), but in a 2005 survey, 66% of the American Heritage Usage Panel accepted it with a singular verb.

Sources

• Merriam-Webster — data, pronunciations and first known use
• American Heritage Dictionary — data, pronunciations and Usage Panel note; Dictionary.com — data
• Cambridge Dictionary — data, plus datum, status, strata, apparatus and tomato; Oxford Learner's Dictionaries — data and data (American English)
• Collins — data; Wiktionary — data, datum and date
• Online Etymology Dictionary — data; Wikipedia — Traditional English pronunciation of Latin
• Yuko Shitara — Survey of American pronunciation preferences, UCL, 1993 (archived copy), with the British poll figures; John Wells — Age grading in English pronunciation preferences, 1995, and LPD polls (archived copy)
• Memory Alpha — "The Child" and Data, Star Trek: The Next Generation