The use of the Ada language in a development project impacts the traditional approach to project planning. The experience at Concurrent Computer Corporation in the development of an Ada compiler, written in the Ada language, showed that the design phase of the project was longer than anticipated. The increased design time significantly decreased the system integration time. In addition, the time spent learning to use the Ada language effectively was a large portion of the total project time. The coding rate was not unusual and the overall project schedule was only 10% greater than the original plan. Initial results also indicate that the resulting product is more reliable when written in the Ada language.