This is a perfect opportunity for to write one of my treatises about the erosion of education and sophistication in the young of today. Due to the proliferation of txting, instant messaging, tv-parents and L33tness.
But, although I agree that many question titles are rife with spelling, grammar, and punctuation mistakes, we have to consider what exactly we want to do about it.
StackOverflow is an open community. Anyone (and everyone) can and should join. This means we are going to have users who are University professors with a few PhDs and years of training, and we will also have some high schools students from France who understand very little English. StackOverflow must be able to handle and deal with each of these appropriately.
There are three categories of actions possible (not exclusive):
This is the quickest and least productive response. (I've left out "ignore" because it isn't an "action" that you take). In downvoting, or even downvoting with a semi-explanatory complaint ("-1 Your title sux") does not actually help the user, because they do not necessarily understand:
A. What in particular is problematic about the title
B. Why poor spelling or grammer is somthign we car about?
But you have successfully indicted that they have failed in some way, so this would act simply as a reminder that you (anonymously) consider them deficient in some way.
This is the preferable solution for titles which have simple spelling or grammar mistakes. The user will receive a notification that their question had been edited, and if they check the history, they will see what you did. You can even add an edit comment "Cleaned up spelling, punctuation and grammar." This way, you have subtly, but not preachily, explained to them that grammar is something that is preferable on the site.
This one is quite difficult to pull off without being obnoxious. We do want to encourage people to modify their behaviour to correctly use the English language, but this is a technical question and answer site, so the only case where it is unacceptably problematic is when the question cannot be understood, otherwise it is merely annoying.
Ultimately, the best solution is to edit to improve the grammar or spelling, and leaving an edit note that explains your edits. Users who are inclined to improve will take note and hopefully do better next time, users who are not inclined to improve, well, there's really ain't nothing you can do about them.
For a further comment about how to improve entire questions, see:
We need to help non-english speakers somehow