Haggadah or Aggadah?

Why do we talk about the הגדה (Haggadah) of Pesach, but normally say Aggada (אגדה) for all other uses? according to the Academy of the Hebrew Language, both terms are identical. The early Hebrew was הגדה, however as Aramaic became more influential people started using the aramaic form and started to use the word אגדה.  Even in recent times you could find both spellings of the word used to describe the Pesach (H)Aggadah.

So, next time an Israeli  instructs you to say Aggadah without a Heh, you can tell him that he is the one who's Hebrew has been corrupted!