The study described here is grounded in naturalistic inquiry, a research methodology that seeks to understand phenomena in context-specific settings. The goal of the study was to identify the beliefs about developing language proficiency of a group of North American French-as-a-foreign language teachers in the specific context of a three-week, NEH-sponsored institute that took place in Lyon, France, and to determine if their beliefs are compatible with the literature on foreign language teaching. The teachers kept diaries in which they recorded their experiences about increasing their proficiency in French. The final data set consisted of 273 pages of handwritten diary entries. Analysis of the data revealed five distinct beliefs and related corollaries about SLA. The number of diary entries that substantiated each belief ranged from 14 to 39, with between 42 percent and 63 percent of the teachers expressing each belief. As in all naturalistic inquiry, generalizing the results of this study to other contexts should not be made. The beliefs found are unique to the context of the three-week institute and to the particular group of teacher diarists. (Contains 1 table.)