"The" (known by grammarians as the definite article) is one of the shortest and most common words in the English language. It may even be the most common word.
It can be pronounced as either "thee" or "thuh" (forgetting, for the purpose of this blog post, such aberrations as "duh").
I'm 69 years old, but until a couple of years ago I didn't realize that there is a thee/thuh rule.
I assumed that the choice was purely personal.
I've never thought much about the choice and assumed that most English-speakers simply knew which sounds better.
Maybe I was taught the rule 60 years ago -- or maybe I was out sick when a teacher taught that particular lesson. I don't remember either parent correcting me for mispronouncing "the."
But, there is a rule (quoted here from Grammar Girl):
- If the word following "the" starts with a consonant sound, you pronounce "the" as "thuh."
- If the word following "the" starts with a vowel sound, you pronounce "the" as "thee."
Now for an exception: Sometime even if "thuh" is the officially correct pronunciation, you can say "thee" for emphasis, as in "It may even be the most common word," which I typed up above.