There has been no published study on personal letters written before an individual's suicidal death hitherto, although studies have been done using diaries. The purpose of this study was to search for trends in the use of particular linguistic categories in a series of personal letters written before an individual's suicidal death. A linguistic analysis of a series of 23 letters written (not suicide notes) by a young man who died by suicide to one friend over a period of two years prior to his death revealed several trends, including a decrease in negative emotion words and an increase in death words. The implication of these trends are discussed.