Final answer:
The correct term to describe the specialized language used by lawyers, often referred to as lawyer speak, is 'legalese'. This type of legal terminology is known for its complexity and is distinct from everyday language, presenting a challenge for those outside the legal profession. The advancement of plain English aims to simplify legal language to be more accessible to the general public.
Step-by-step explanation:
Lawyers often use legal terminology that others may not be familiar with. This specific type of language is sometimes referred to as lawyer speak. When considering the options provided - legalese, legal jargon, jurisdiction, and legal vernacular - the correct term that fits the blank in the student's question is 'legalese'. Legalese mainly focuses on precedent and aims to be clear, consistent, and complete to avoid any ambiguity, especially in legal documents such as briefs.
The term legal jargon is also associated with specialized terms used by lawyers, yet 'legalese' more specifically connotes the often arcane and complex language used in legal documents. This contrasts the recent trend toward plain English which simplifies the terminology to make it understandable for those outside the legal profession. The legal language must be clear enough to avoid misinterpretation, helping to ensure that judicial decisions are made on the basis of well-communicated facts and arguments.
In the context of improving legal communication, plain English reforms aim to make legal writing more accessible thus reducing the use of legalese. The linguistic reforms help to empower and include those who are not part of the legal profession. Such changes reflect an understanding of how language can exclude or include various groups within society.