We normally pronounce "the" with a short sound (like "tha"). But when "the" comes before a vowel sound, we pronounce it as a long "thee".
VOWEL SOUND WITH 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 ugly fruit thee ugly fruit
We must understand that it doesn't matter how we write it, what matters is how we say it. So we use long "thee" before a vowel sound, not necessarily before a vowel.
Here are some cases:
WE WRITE WITH WE SAY WITH
the house consonant (h) tha house consonant sound
the hour consonant (h) thee our vowel sound
the universe vowel (u) tha yuniverse consonant sound
the umbrella vowel (u) thee umbrella vowel sound
the earth vowel (e) thee earth vowel sound
