Earn at least an undergraduate degree (although a master's degree or Ph.D. is preferred) in linguistics. The more specialized the field, the better. Other possible degree programs are psychology, criminology or criminal justice. If called on to testify during a criminal investigation, your credibility largely rests on your academic credentials. Hofstra University in New York offers a course in forensic linguistics as part of its Continuing Education program, which delves into dialectology briefly. Hofstra also offers a more generalized linguistics major program. Enroll in classes in the math, social and natural sciences fields.
Cultivate strong interviewing skills as you will be working with people from varied cultural and ethnic backgrounds. Develop proficiency in a number of languages and dialects. This is especially critical since linguistic origin analysis (often used to determine origin in cases where a person seeks political asylum) is becoming increasingly complicated. Many dialects are shared across borders or are constantly evolving.
Get accredited by a trade association such as the American Academy of Forensic Science's Board of Scientific and Technical Advisors. Continue to expand your skill set and gain recognition in your field by attending conferences and publishing articles. Your reputation is further solidified by being called as an expert witness at a criminal case: for example, to rule out whether an unidentified caller on a tape is from a province in Afghanistan.
Join a professional organization, such as The Association for Linguistic Evidence (TALE), by submitting character references and a resume demonstrating a track record in forensic linguistics. TALE is part of the Institute for Linguistic Evidence, a nonprofit research organization dedicated to improving forensic linguistic methodology, according to the organization's website. Continue networking and marketing yourself at conferences and organization meetings by touting your qualifications as an expert in your field.