Comment 5 for bug 454279

I also made a syntactic argument on the wikitionary page:

I mean ... syntactically speaking, it acts as a determiner, and never as a noun (and thus, cannot be a syntactic pronoun). So, for example, one can say:

This is the book.
This is my book.

so, syntactically, its a determiner, like "the". Now, other pronouns behave much like nouns:

This is I.
This is me.
This is him.

But "my" cannot behave like a noun: you can't say:

*This is my.

nor could you say:

*This is the.
*This is a.

Perhaps its a noun modifier ("_nn") ? No. For example, the noun "goal" can be a noun modifier:

He stood on the goal line.

But pronouns can never be noun modifiers -- you can't say:

*He stood on the him line.
*He stood on them line.

while "my" can be used in this way:

He stood on my line.

I cannot think of a single example where "my" behaves like a noun or other pronouns, syntactically speaking. As a part of speech, calling it a pronoun sure seems wrong to me.