National Board of Professional Teaching Standards (NBPTS) certification offers experienced teachers opportunities via written portfolios to match their practice to NBPTS standards. In creating standards and requiring teachers to argue in writing that they have realized the standards in their teaching, NBPTS offers a national discourse. However, since teachers' working knowledge is local, contextualized, personal, and oral, teachers may find difficulties in entering such discourse. This study followed four experienced teachers who were in an NBPTS support group and applying for NBPTS certification. The program provided intellectual and practical support on a monthly basis, with support varying by certification area. Researchers followed participants as they prepared portfolios for NBPTS certification, collecting data via participant observation during support groups and certification area groups; field notes during working sessions with drafts of portfolio pieces; and two interviews with each participant. Interviews asked about background, teaching site, attitude toward the NBPTS standards and process, and problems or successes in preparing portfolios. Data analysis indicated that all four participants had difficulty with some parts of the process of NBPTS candidacy, particularly with representing their practice in writing. Problems occurred in the areas of writing apprehension, representing tacit knowledge, understanding sample logic, negotiating the standards, and providing evidence from teaching. Candidates who were most successful were able to assume the NBPTS discourse values. (Contains 35 references.) (SM)