You will definitely have noticed those little words that precede and modify nouns. They are of three types: determiners, articles and quantifiers.
Articles will tell the reader whether we are referring to a general or specific thing.
A teacher needs patience. (General)
I would like to talk to the head teacher. (Specific)
Quantifiers tell us how much or how many. Examples are: much, many, a lot of, several, some, few, a great deal of, plenty of
Native English speakers have no difficulty choosing the right article or determiner to precede a noun or noun phrase. However, non-native English speakers and writers often find it difficult to use these words correctly. On the bright side, most of these errors are not serious. You will still be understood even if you omit articles and determiners. However, if you are serious about writing good English, you cannot ignore these little words.
Here is a quick overview of articles, determiners and quantifiers.
A determiner will always be followed by a noun. Of course, sometimes the noun can be omitted. This usually happens when the meaning is clear.
Some types of determiners are limited. For example, there are only three articles (a, an, the) and a handful of possessive pronouns (mine, his, hers, ours, yours, theirs, whose etc.)
Determiners serve the same purpose as adjectives: they are used to modify nouns. However, adjectives are limitless. And as language evolves new adjectives may appear. However, we are unlikely to have a fourth article in addition to the three we already have. That is why some grammarians insist that determiners should be considered as another part of speech.