Prosodic stress and topic detection in spoken sentences

The relationship between acoustic stress and the information content of words is investigated. On the one hand, the average acoustic stress is measured for each word throughout each utterance. On the other hand, an information retrieval (IR) index is calculated, based on the word frequency throughout the particular spoken sentence and throughout the collection of analysed spoken sentences. The scatter plots of the two measures (average acoustic stress on the y-axis and IR index on the x-axis) show higher values of average acoustic stress with increasing IR index of the word in the majority of the analysed utterances. A statistically more valid proof of such a relationship is derived from a histogram of the words with high average acoustic stress vs. the IR index. This confirms that a word with high average acoustic stress also has a high value of the IR index and, if we trust IR indexes, also a high information content.