Before proceeding, make sure you have CFW installed. If you don't have it installed, you can find a guide here.
In the past, you needed an actual software to extract the UMD, now the function is built into the VSH Menu. Press select and the VSH Menu will pop up. Yours might look a little different, I have a plugin that changes the appearance of the VSH Menu, but the options are still the same. Go down to usb device and press the right arrow until you get to UMD Disc. Once you have that selected, back out of the VSH Menu and plug your PSP in to a computer. Find the ISO file, the file name should start with "UMD". Now take that ISO file and store it somewhere safe. Now go back to the VSH Menu and set it back to memory stick, now you can put that ISO file from earlier into the ISO folder now! You are now able to patch the iso file for the English translation.