How should the session chair introduce presentation titles which are ungrammatical?
I would not know any reason that forces chairs to read the title of the talk.
On the contrary, even with grammatically correct titles, it feels rather lazy and unnatural to me.
Also there is a certain kind of speaker who will read their title, no matter what you do.
This is a little bit less awkward, if you haven’t read the title already.

Hence, if I am sufficiently comfortable with the subject (which I think I should be when chairing), I would always attempt to paraphrase the title.
For example, suppose your title is:


  How should the session chair introduce presentation title which ungrammatical?


Then I could introduce you with:


  The first speaker is Rebecca J. Stones, who investigated ungrammatical presentation titles and will talk about how chairs should introduce them.