How can I unlock my tablet that my password is in English and the keyboard is in Arabic?
What is your OS? Here is a link that might help you:
Now here are some scenarios:
If you are in Jellybean and you only have the stock Jellybean password, then I'm sorry to say you need to take a drastic measure in opening your tablet which is doing a factory reset. However, on the link above it will tell you that you can unlock your device by using your Google account online. I don't really know the details but that might help you.
If you are using another keyboard from the Play Store, chances are you can edit the settings on the keyboard itself. This could appear in the form of a settings button (a circle with a dot on the center) where you can set up the language of the keyboard or you are using Hacker's keyboard you can swipe the spacebar and the keyboard will change the language.
I strongly suggest you add what OS and keyboard configurations you are using(activated keyboards, current keyboard used) to your question so that others might add more helpful answers.