What is Law French?

Legal Definition
Law French is an archaic language originally based on Old Norman and Anglo-Norman, but increasingly influenced by Parisian French and, later, English. It was used in the law courts of England, beginning with the Norman Conquest by William the Conqueror. Its use continued for several centuries in the courts of England and Ireland.
-- Wikipedia
Legal Definition
An altered form of the Norman French language, arising in England after the Norman conquest of 1066. It became the main language of the English legal system and remained in heavy use for several centuries - until its gradual replacement by Law Latin and English.
Legal Definition
The Norman French language, introduced into England by William the Conqueror, and which, for several cenfuries, was, in an emphatic sense, the language of the English law, being that in which the proceedings of the' courts and of parliament were carried on, and in which many of the ancient statutes, reports, abridgments, and treatises were written and printed. It is called by Blaekstone a "barbarous dialect," and the later specimens of it fully warrant the appellation, but at the time of its introduction it was, as has been observed, the bast form of the language spoken in Normandy. Burrill.
-- Black's Law Dictionary