Comparison with determiners and adjectives
Possessive determiners (possessive adjectives) have features of both determiners and adjectives:
Possessive determiners, as used in English and some other languages, imply the definite article. For example, my car implies the car that belongs to me/is used by me; it is not correct to precede possessives with an article (*the my car) or other definite determiner such as a demonstrative (*this my car), although they can combine with quantifiers in the same ways that the can (all my cars, my three cars, etc.; see English determiners). This is not the case in all languages; for example in Italian the possessive is usually preceded by another determiner such as an article, as in la mia macchina (“my car”, literally “the my car”).
Possessive determiners may be modified with an adverb, as adjectives are, although not as freely or as commonly as is the case with adjectives. Such modification is generally limited to such adverbs as more, less, or as much … as (comparative) or mostly (superlative), for example in This is more my team than your team, This is less my team than your team, This is as much my team as your team, and This is mostly my team.
While some classify the words my, your, etc. as possessive adjectives, others, due to the differences noted above, do not consider them adjectives – at least, not in English – and prefer possessive determiners. In some other languages the equivalent parts of speech behave more like true adjectives, however.
The words my, your, etc. are sometimes classified, along with mine, yours etc., as possessive pronouns or genitive pronouns, since they are the possessive (or genitive) forms of the ordinary personal pronouns I, you etc. However, unlike most other pronouns, they do not behave grammatically as stand-alone nouns, but instead qualify another noun – as in my book (contrasted with that’s mine, for example, where mine substitutes for a complete noun phrase such as my book). For this reason, other authors restrict the term “possessive pronoun” to the group of words mine, yours etc. that substitute directly for a noun or noun phrase.
Some authors who classify both sets of words as “possessive pronouns” or “genitive pronouns” apply the terms dependent/independent or weak/strong to refer, respectively, to my, your, etc. and mine, yours, etc. For example, under this scheme, my is termed a dependent possessive pronoun and mine an independent possessive pronoun.
Possessive determiners in English
The basic pronominal possessive determiners in modern English are my, your, his, her, its, our, their and whose (as in Whose coat is this? and the man whose car was stolen). As noted above, they indicate definiteness, like the definite article the. Archaic forms include thy and mine/thine (for my/thy before a vowel). For details, see English personal pronouns.
Other possessive determiners (although they may not always be classed as such, though they play the same role in syntax) are the words and phrases formed by attaching the clitic -‘s (or sometimes just an apostrophe after -s) to other pronouns, to nouns and to noun phrases (sometimes called determiner phrases). Examples include Jane’s, heaven’s, the boy’s, Jesus’, the soldiers’, those men’s, the king of England’s, one’s, somebody’s.
For more details of the formation and use of possessives in English, see English possessive. For more details about the use of determiners generally, see English determiners.