Hi Gringo300.  I was very interested to see your note on Wiglaf's page that you are wanting to find out about the prehistory of English.  I have just been working on a couple of articles which might help you.  You can help me by looking at these and telling me if they are understandable as they are and whether they meet your needs; because you are probably the kind of person they are written for.  You will find these at: Germanic weak verb, West Germanic strong verb, Ablaut and Umlaut.  I hope you enjoy these.  Please give me your feedback.