Many websites on English grammar make mention of possessive adjectives. They use this term for words like my, his, her, our, your, etc. which always occur before nouns, typically to indicate possession. This would seem to make sense. After all, there is a similarity between the following:
- my daughters
- lovely daughters
However, the fact that my and lovely both occur before the noun daughters does not mean that they are both adjectives.
Adjectives are often said to be describing words: they ascribe a property to the noun that they accompany (‘being lovely’). By contrast, words like my, his, her, etc. have a ‘specifying’ or ‘identifying’ function. They belong to the class of determiners, along with a, the, this, that, those, etc. Compare the following:
- a cat
- the cat
If you and I are talking, and I use the former phrase then I’m talking about a cat that is not known to you: it has as yet not been identified. The property of not being identifiable is called ‘indefiniteness’. Conversely, the property of being identifiable is called ‘definiteness’. So, when I use the phrase the cat in a conversation with you then you are familiar with (or I’m assuming that you are familiar with) the particular cat I’m talking about: it is an identifiable cat. Similarly, when I use the phrase my daughters then the individuals I’m talking about are identifiable to you.
Adjectives are grammatically different from determiners: typically they have comparative and superlative forms: lovely, lovelier, loveliest, and they are often gradable: very lovely. However, determiners cannot be modified in this way. We can’t say my-er, my-est or very my.