American law and English law belong to the same legal tradition, called the common law characterized by a case-law system based on judicial decisions and the rule of precedent. There are indeed common features between the American and the English common law systems. There is a common language with close expressions, but also similar concepts, principles and procedures. But how common are in fact the American and British legal systems? This paper aims at finding some possible answers through a legal and linguistic analysis of some US and UK superior court decisions.