This study sought to determine under what conditions 14 recent Mexican immigrant high school students thought they used and acquired English as a Second Language (ESL) in an "English Only" high school in California. Each of the 14 students was interviewed at least twice and "shadowed" for 2 days in school. Follow-up interviews and observations provided verification, correction, and clarification of self-reports. Interviewees' insights were compared to those obtained from teachers, counselors, and administrators. In a school with 49% Hispanic and 24% limited English proficient (LEP) populations, students explained that their major linguistic problems were based on a lack of opportunities to understand and use English for social and academic purposes both in and out of the classroom. Student suggestions for the improvement of English language learning are presented and discussed. Six appendixes contain an introductory letter to teachers, a student questionnaire, a language log form, a parent and student participation agreement, a follow-up note to teachers, and a sample page of a coded interview. (Contains 142 references.) (MDM)