This paper makes an attempt to improve the retrieving algorithm for an intelligent communication instrument. The instrument is developed for visually impaired computer users, and it converts texts displayed on a computer screen into audio messages to help them operate the computer. The conversion is performed based on a user dictionary, and a retrieving algorithm is needed to search the dictionary. In order to accelerate the retrieving speed, we adopt an index table when retrieving the first two alphabets of a word in the dictionary. The time for retrieving words is measured in the experiments. The experimental results reveal that the retrieving operations can be finished within an acceptable time.