And what is Yeshivish? Wikipedia answers:
Yeshivish (Yiddish: ישיבֿיש), refers to a sociolect of English spoken by yeshiva students and other Jews with a strong connection to the Orthodox yeshiva world.Well, that clears it up! Fortunately, the Forward's Philologos has published an article, How To Understand Yeshivish, that mamash does clear it up.
Here is one example of Yeshivish as she is spoke:
The lechatchila time for shacharis is neitz. B’dieved, if a person davened from amud hashachar and onwards he is yotzei. In a shas hadchak he may daven from amud hashachar and onwards lechatchila…. After chatzos it is assur to daven shacharis. One should wait till after mincha and then daven a tashlumin. The possibility for a tashlumin doesn’t exist for someone who was bemaizid.
For more examples of everyday Yeshivish, Abq Jew refers you to The Yeshiva World News. Bet you didn't know that was out there, did you?
But here's a great video example from the kiruv organization Oorah. Enjoy!