How to Pronounce "the" in English

Normally, we pronounce "the" with a short sound (like "thuh"). But when "the" comes before a vowel sound, we pronounce it as a long "thee".

vowel sound	we write	we say
A	the apple	thee apple
E	the egg	thee egg
I	the ice-cream	thee ice-cream
O	the orange	thee orange
U	the ugli fruit	thee ugli fruit

It is important to understand that it is what we say that matters, not what we write. It is the sound that matters, not the letter used in writing a word. So we use a long "thee" before a vowel sound, not necessarily before a vowel. Look at these cases:

we write	with	we say	with
the house	consonant (h)	thuh house	consonant sound
the hour	consonant (h)	thee our	vowel sound
the university	vowel (u)	thuh youniversity	consonant sound
the umbrella	vowel (u)	thee umbrella	vowel sound

Emphatic the [thee]
When we wish to place emphasis on a particular word, we can use "emphatic the" [thee], whether or not the word begins with a consonant or vowel sound. For example:
A: I saw the [thuh] President yesterday.
B: What! The [thee] President of the United States?
A: Yes, exactly.

When to Say "a" or "an" 

The indefinite article is a or an. But how do we know when to say a and when to say an?
The rule is really very simple. It depends on the sound at the start of the following word. (It does not depend on the way we write the following word, it depends on the way we say it.)

A + consonant sound

If the following word starts with a consonant sound, then we say a.

a cat

a game of golf

a human emotion

a Peruvian

a very fat woman

AN + vowel sound

If the following word starts with a vowel sound, then we say an.

an apple

an extremely easy job

an interesting film

an old man

an umbrella

The importance of sound

Normally, we pronounce consonant letters with a consonant sound, and vowel letters with a vowel sound. But there are some exceptions. The rule about a or an is still the same. You just need to think about the sound, not the writing. Look at these examples:

consonant letter with vowel sound
an honest man	on-est
an hour	our
an FBI agent	eff-bee-eye

vowel letter with consonant sound
a European country	you-ro-pe-an
a one-day conference	won-day
a university	you-ni-ver-si-ty

• When the definite article (“the”) comes before a word that begins with a vowel, pronounce it like “thee.” E.g. “<thee> elephant”
• When “the” comes before a word that begins with a consonant, pronounce it like “thu” (with a schwa sound). E.g. “<thu> car”

If you emphasize “the,” it is often pronounced “thee,” even when it comes before a word beginning with a consonant. Try saying, “He is the master of English.” It comes out sounding like “thee,” doesn’t it?
One writer on a linguistics mailing list claims that some people pronounce “the” as “thu,” regardless of the word that follows. However, this pronunciation isn’t standard (when followed by a word beginning with a vowel). It might be attributable to a regional or class dialect, but I don’t know for sure.

You may find additional information at one of these places:

• The British Council: The United Kingdom’s international organisation for educational and cultural relations
• International EFL Cafe