This afternoon a student asked me, "When do you pronounce "the" /ði/ and when do you say /ðə/?" My quick answer was something about a vowel sound but then when I started to give examples, it got confusing.
If you look around the internet, you'll find conflicting answers depending on the dialect of English being spoken. Dictionary.com says that it's /ði/ before a vowel sound and /ðə/ before a consonant sound.
The part that can be confusing is that it's before a vowel sound, not a vowel. EnglishClub.com explains that part. For example, "university" begins with a vowel but it's actually the sound of the consonant, /y/ (also written as /j/).
