Hints are a useful and common pedagogical tactic, particularly in one-on-one tutoring sessions. Hints can serve: (1) to activate otherwise inert knowledge making possible its recall, or (2) to stimulate the generation of inferences required to complete a task using knowledge thought to be available to the student. W e report on the analysis of one-on-one tutoring sessions conducted by two tutors using a computer system to capture the dialogue. Hints either expUcitly convey information to the student or they point to information presumed to be available to the student. W e have identified at least 10 different forms of hints used by our tutors. T h e two tutors differ in the total n u m b e r of hints they generate and in the prevalence of hints of different types. Our results are being applied to the design of an intelligent tutoring system (ITS) with a natural language interface.

By student initiatives we mean productions which the student could reasonably expect to modify the course of the tutorial dialog;ue. Asking a question is one kind of student initiative. This paper describes a system called CircSim-Tutor which we are building, the background of the project, the 28 hour-long tutoring sessions jmalyzed in this paper, and the analysis done. It compares our work to previous work, gives a classification of the student initiatives found and of the tutor's responses to them, and discusses some examples.