Does Grammar Affect your Ranking?
According to Rusty Brick from Search Engine Roundtable, poor grammar in title tags does not affect your rankings.
There have been questions as to whether poorly constructed title tags are to blame for drops in rankings but according to Yahoo, such is not the case (at least for Yahoo).
Rusty states that many title tags don’t read correctly on purpose (i.e. ranking for commonly misspelled words). The important point to make is that title tags should be pithy and read quickly.