In 1991, the Department of Social and Health Services (DSHS) in Washington State initiated an effort to certify its bilingual staff, social service and medical interpreters, and translators working for DSHS throughout its many divisions and programs. This effort was the culmination of lawsuits and civil rights complaints brought against DSHS for not providing equal access to services for Limited English Proficient (LEP) clients. As part of a consent decree, DSHS agreed not only to provide (and pay for) interpreters for clients, but also to ensure the quality of interpreter services provided. DSHS chose to ensure quality through the development and administration of standardized tests.

The Language Testing and Certification program (LTC) was created to develop systems, methods, procedures, and policies in carrying out the department's commitment. A Code of Professional Conduct was developed for Language Interpreter and Translator. See Interpreter Code of Ethics»