This paper proposes a method for detecting word boundaries. This method is based on the behaviour of the pitch frequency across the sentences. The pitch frequency (F0) is found to rise in a word and fall to the next word. The presence of this fall is proposed as a means of detecting word boundaries. Four major Indian languages are used and the results show that nearly 85% of the word boundaries were correctly detected. The same method used for German language shows that nearly 65% of the word boundaries were correctly detected. The implications of these result in the development of a continuous speech recognition system are discussed.