Pronunciation of "candidate"

There's more than two pronunciations, depending on who's talking, how fast they're talking, and how excited they are.

It's normal to reduce a vowel to shwa /ə/ when it's unstressed, and even when it has only a secondary stress, like the last syllable of candidate. The faster and more excited the speaker, the more likely they are to reduce the vowel.

And to do other things. The first /d/ is frequently deleted: /'kænədet/, and the second /d/ is often reduced to a flap: /kændəɾet/. All of these are independent processes, and may happen together or separately, so all combinations occur.

The technical term for this is Fast Speech Rules, btw. It's a big topic in phonology.

I can't speak for the U.K., but, in the U.S., both are used often enough that neither would sound out-of-place or unusual.

Forvo had six pronunciations (5 from the U.S., 1 from the U.K.), and both pronunciations were given.

I also went to YouTube and queried "CNN Candidate". The first two selections I listened to provided a sample with each pronunciation:

• at the 0:06 mark of this video, we hear kandidāt,
• yet 28 seconds or so into this video, the reporter says kandidit

_{By the way, I only listened to these videos long enough to hear a reporter say the word candidate.}
^{I'm not endorsing any candidate, nor attesting to the validity of the content of these videos.}

I agree with John Lawler that there's more than two pronunciations. They are not shown in most dictionaries because there are rules of how a word's pronunciation gets changed in rapid speech. What you usually see in a general dictionary is how a word is pronounced in isolation or when you enunciate it.

A good pronunciation dictionary, like the Longman Pronunciation Dictionary by Professor Wells (Wells 2008), gives five variants for the word "candidate" (used in BrE):

/ˈkændɪdeɪt/

/ˈkændədeɪt/

/ˈkændɪdət/

/ˈkændədət/

/ˈkændədɪt/

By no means this list is exhaustive.

However, Alan Cruttenden (2008) argues that /ə/ in -ate is more common than /ɪ/, and it's a part of a more general trend, which is becoming "increasingly noticeable among RP speakers of the middle and younger generations" (p. 108).