I've seen many non-native speakers of English not making use of indefinite articles, presumably since their first language did not contain them. Thinking about this, and about the fact that even in English we get along fine without a plural indefinite article (only singular), I wonder why the indefinite article in theory is helpful. It seems to be an arbitrary particle, without the use of which we lose no meaning:
A tall man saw a black dog. --> Tall man saw black dog.
This sounds stilted; but if we switch gears to plural nouns, it sounds better without articles because English has no plural indefinite articles, only singular:
Tall men saw black dogs.
The presumption here is that we could understand the nouns in the above sentences as if they had invisible indefinite articles. Therefore, no article = indefinite article, as in many other languages, and as with English plural nouns. My basic question is this: What does the indefinite article accomplish? I'm not asking if we should stop using it - obviously it's here to stay for the time being, but is there something I'm missing that supports its existence? Was there a logical reason it came into being, or did it have a subconscious debut? (OK, I'm a language cynic, but deep down, so are you. ;)
Apparently the article an (a being a variant) derives from the OE ān meaning "one, in a weakened sense". Is there any further etymology of the indefinite article, or did its usage arise around 950 A.D.? Did English always have an indefinite article? I'm asking because I want to see intermediate usages if possible: usages of a while a was still being born.