The personal website of the American medievalist and Latin scholar Daniel Williman contains an outstanding work on legal English: “Legal Terminology: An Historical Introduction to the Technical Language of the Law.” For each area of law Professor Williman provides historical background, followed by related terminology and definitions. First published in book form by the University of Toronto Press in 1986, a glance at the Table of Contents of this work shows just how complete this overview is:

1. Language and European History
2. Legal History and Legal Terminology
3. Litigation, Pleading and Trial
4. History I: Roman Civil Law
5. Contracts and Debts
6. Judgement and Enforcement
7. History II: Canon Law and Jus Commune
8. Wills and Estates
9. Penal Law
10. History III: Germanic and French Custom, Feudal Law, Law French
11. Domestic Relations
12. Crime
13. Documents, Instruments, and the Record
14. History IV: English Common Law
15. Real Property
16. Criminal Procedure
17. Equity
18. Commercial Law
19. History V: North American Reception of European Law
20. Logical Argument and Evidence
21. Torts
22. Corporation, Partnership, and Securities
23. Sovereignty and Conflict of Laws

It is possible to browse the work by chapters using the links above, or view it in its entirety (with its Preface, Introduction, References and Index to Latin maxims) here: http://www.corsanoandwilliman.org/latin/work/legalterminology.htm#contents