Is the word 'the' unnecessary in the English language?

Solution 1:

No, "the" isn't unnecessary in the English language. It has an important role as a familiar component of the English language, of course, but it is also important functionally.

For example, there is a spectrum between most indefinite and most definite. That is, you might talk about something without caring about the specific instance (e.g. he ate an egg - it doesn't matter which egg), or you might care about which specific instance you're talking about (e.g. he ate the egg - that particular one).

In particular, 'the' helps to differentiate between referencing a specific instance and the essence of that specific instance. Here's an example:

• "He is a king" - he is one king out of an unspecified number.
• "He is the king" - he is a particular king.
• "He is (null article) king" - he embodies the essence of kingship.

Compare the last two by considering this sentence: "He may be the king but he isn't king". This expresses that although he may have the title of 'king', he doesn't have something of the essence of one. It might be used to describe a pretender to the throne who manages to be crowned, but who doesn't hold the loyalty of his (supposed) subjects. The definite article is instrumental in teasing out this nuance.

Solution 2:

It all depends on what you mean by 'necessary'.

If you mean to make things follow English grammar the answer is a definitive 'yes'. The grammar demands it. Dropping it is what foreigners who don't have articles in their native language do mistakenly. But it's obvious you knew that.

So let's suppose, counter to reality, that we don't care about grammar, or that English grammar allows dropping articles.

If you mean to communicate the idea of a previously mentioned item, also yes, it is very necessary, if you intentionally want to point out this previous mention. Intentional, deliberate meaning is necessary. If you need for it to be explicit, then it is necessary.

If the context helps to disambiguate that it is a new thing or a previously mentioned thing, then maybe it's not necessary. In, "I ate cookie; cookie made me sick", it would be perverse for the second instance to refer to anything other than the first instance of 'cookie'.

Now if what you're really asking is whether a definite ness (the need for a definite article) is necessary in all languages, then that is a no. Many languages do not have a need for an obligatory article. (most European languages need an article; Russian is a big exception). And if you need to point out a new thing vs an old thing, use 'one' or 'this' respectively ('I ate one cookie; this cookie made me sick').

As to your expected phenomenon, I don't want you to go away thinking that we don't see what you see. I have to agree with you that you could eliminate almost all articles and you'd still understand what the author intended.

But as to your essential question, why isn't 'the' just removed from the English language, languages just don't work like that. No authority says what's in a human language; it's all by common usage.

Maybe you mean why do people bother to continue using it since it wastes so much energy. Again appealing to human language, it's not a uniform coding device. Word frequencies almost always follow some kind of Zipf curve. Get rid of one and the language will recalibrate, pushing some around. There will always be a highest frequency word. Also, because of expectations of English, just the slot to fill, that's enough to need it. It's sometimes a very useful semantic notion, to differentiate between a new thing and a previously mentioned thing. No big deal to always mention it. You always can. You can always do this in Russian; of course you'd sound weird for always insisting on specifying which noun you are referring to, but it won't be ungrammatical.

This all seems so negative, not the direction you were hoping for. Sure, if we were designing a whole new language, we probably wouldn't make articles obligatory, just like we probably wouldn't gender all our nouns or have inflections for case or agreement or any similar redundancies. But since definiteness is expected by speakers of English, articles to sign this are necessary.

So in the end, the answer 'No, you can't remove it because that's not grammatical English' is legitimate. And the answer to a reworded question is 'Yes, a differentiation between a definite or indefinite noun is only optional if you look at all languages'.