Hi. I speak English very bad, but i will try to explain. Pdf files - it is pictures gathered for convenience. To translate from them the text, you at first need to recognition this text. Program FineReader is for this purpose used. After that it will be necessary to edit files by means of graphic programs (for example Photoshop) and manually to write, the text recognited and translated by you.
Easier to ask necessary for you scans, it is possible they is in English.