I often forget to use articles when writing English because of the inertia from using Chinese, for example when I say “a recent favorite spot”, it’s more natural for me to just express “recent favorite spot”. Only after a long second I realized there should be a “a” or “my”, otherwise I should make it “spots”. Of a sudden, I get a sense of the differences of nouns between Chinese and other Indio-European languages.
Most widely used languages require a strict distinguish on its singular or plural nouns usage. Half of the reason coincidently came from the PIE (Proto-Indo-European) tradition, for its highly inflectional characteristics has a complex conjugation system, it even has a dual number. Among the large number of languages inherited from PIE, English was the rebellious one who abundened lots of conjugation and became simply to use, especially when compared with languages like Germany.
Singular or plural states of nouns was trying to solve the efficiency problem, keeping as much important information for both parties as possible in communication. One enemy, or multiple enemies are different for people who live in the ancient tribes, as well as the importance of one unit of food versus ten unit of food.
So it is crucial that what exactly thing people are describing, the shape, the texture, the quality, the color, etc. The “s” in the “two apples” ensures that listeners would know there are more than one apple even if they missed the “two” word.