Why does English need an article before any noun?

Solution 1:

Well, first of all, we don't need an article before any noun. I can say:

I like dogs.

As to your question of why, the answer is, "because that is how English works".

The articles perform a discourse function, by indicating new and old information. They often evolve from demonstratives (e.g. "this" and "that"). They evolve independently in unrelated languages. Normally, once an article system becomes a part of a language, it is an all-or-nothing thing. This is not unlike a verbal inflection system, a gender system, or a case system; once the system is in place, it is not optional.

Aside from this, there isn't really a more concrete reason for "why" English works this way.

Solution 2:

I could just as easily flip this around and say, why does your native language not use articles? To me:

I have dog

Isn't specific enough. Do you have one dog? Multiple dogs? A specific dog?

My point is, different languages have different rules, which make sense to native speakers because that's what they're used to. Consequently languages with different rules make less sense.

Solution 3:

In some languages it's not necessary to use articles before a noun. Persian and Turkish are the examples. For example:

I have dog.

It means that I have a dog. So not using an article before a singular noun is similar to using an article. Also they can use other kinds of articles after the noun.

In these languages: I have dog. = I have a dog.

But in some other languages like English and Arabic you should use an article before a noun to make it clear and specific. Otherwise it's not clear for the reader. So I think that depends on the language.

Solution 4:

This is not an answer to the question about English articles; but it seems from comments that you may actually be more interested in how to say you keep an unspecified number of dogs. So, some alternative ways one could achieve that:

• Make a more specific statement mentioning one dog:

[Showing someone a photo.] This is my dog Bruno.

• Make a statement going covering a wide time period:

I’ve owned dogs for about ten years now.

(This implies you’ve had more than one dog in total, but leaves open how many you own now.)

• Make a statment which is not directly about the dogs you own, but implies their existence:

Oh, damn! I forgot to buy dog food today!

I’m definitely a dog person! I’d get really lonely living without a dog.