Did you ever think about the word "the"? I know I never did. I never looked it up before. I can use the word quite well but to tel the truth I would be at a loss to define it or to explain why we use it.
Are you aware that the word "the" when written gives no hint that it is pronounced in at least two ways. Say out loud "the apple". Listen to how you pronounce it. Then say "the pear". Try it with some other words and you will discover by and by that "the" before a word beginning with a vowel is a bit more like saying "thee". Try it a few times with various words such as "the dog" or "thee dog" "the onion" or "thee onion". See how you pronounce the word.
Most of us have used the word all our lives and were never aware of how we pronounce it. It must drive foreigners crazy.
Here is the definition of "the" from the Merriam Webster Dictionary. I have read it and promptly forgotten what it says.
Main Entry: 1the
Pronunciation: before consonants usually [th]&, before vowels usually [th]E, esp Southern before vowels also [th]&; for emphasis before titles and names or to suggest uniqueness often '[th]E
Function: definite article
Etymology: Middle English, from Old English thE, masc. demonstrative pronoun & definite article, alteration (influenced by oblique cases -- as thæs, genitive -- & neuter, thæt) of sE; akin to Greek ho, masculine demonstrative pronoun & definite article -- more at THAT
1 a -- used as a function word to indicate that a following noun or noun equivalent is definite or has been previously specified by context or by circumstance <put the cat out> b -- used as a function word to indicate that a following noun or noun equivalent is a unique or a particular member of its class <the President> <the Lord> c -- used as a function word before nouns that designate natural phenomena or points of the compass <the night is cold> d -- used as a function word before a noun denoting time to indicate reference to what is present or immediate or is under consideration <in the future> e -- used as a function word before names of some parts of the body or of the clothing as an equivalent of a possessive adjective <how's the arm today> f -- used as a function word before the name of a branch of human endeavor or proficiency <the law> g -- used as a function word in prepositional phrases to indicate that the noun in the phrase serves as a basis for computation <sold by the dozen> h -- used as a function word before a proper name (as of a ship or a well-known building) <the Mayflower> i -- used as a function word before the plural form of a numeral that is a multiple of ten to denote a particular decade of a century or of a person's life <life in the twenties> j -- used as a function word before the name of a commodity or any familiar appurtenance of daily life to indicate reference to the individual thing, part, or supply thought of as at hand <talked on the telephone> k -- used as a function word to designate one of a class as the best, most typical, best known, or most worth singling out <this is the life> <the Pill> -- sometimes used before a personal name to denote the most prominent bearer of that name
2 a (1) -- used as a function word with a noun modified by an adjective or by an attributive noun to limit the application of the modified noun to that specified by the adjective or by the attributive noun <the right answer> <Peter the Great> (2) -- used as a function word before an absolute adjective or an ordinal number <nothing but the best> <due on the first> b (1) -- used as a function word before a noun to limit its application to that specified by a succeeding element in the sentence <the poet Wordsworth> <the days of our youth> <didn't have the time to write> (2) -- used as a function word after a person's name to indicate a characteristic trait or notorious activity specified by the succeeding noun <Jack the Ripper>
3 a -- used as a function word before a singular noun to indicate that the noun is to be understood generically <the dog is a domestic animal> b -- used as a function word before a singular substantivized adjective to indicate an abstract idea <an essay on the sublime>
4 -- used as a function word before a noun or a substantivized adjective to indicate reference to a group as a whole <the elite>
---Al