This paper examines changing emotional tone in dialogue and its prosodic correlates. 'Feeltrace' has been developed to trace emotional tone over time. It uses a simple but tractable representation of emotional tone based on psychological research. Listeners rated the emotional tone of arguments between friends (in real time) by positioning a pointer in a two-dimensional space whose axes are evaluation and activation. Feeltrace ratings were correlated with prosodic measures. The strongest correlations involve change in emotional tone, with change in activation level the most clearly and consistently marked. The common marker of change in evaluation involves pausing. However the correlation patterns are not the same for different speakers, and several features have variable significance.