A study of the gravity of non-native speakers' speech errors, particularly as viewed in the workplace, was based on two assumptions: that certain features of spoken English contribute more to speech acceptability than others, and that native speakers have an internalized, ordered list of criteria for making judgments about non-native speakers' English. The study had three groups of subjects: 70 students of English as a second language (ESL) who provided speech samples; 29 ESL teachers who judged the samples' acceptability, identified non-native features using a checklist, and ranked the five least acceptable features; and 21 naive judges chosen on the basis of their occupations, with little linguistic or foreign language training and limited exposure to ESL, who judged which of a pair of artificial speech samples was more acceptable. While results suggest a hierarchy of speech sound acceptability generalizable on the basis of occupation, further research on isolating features and other independent variables is recommended. Although some variation from earlier hierarchies was found, the methodology used was determined to be viable for extending the hierarchy. (MSE)