Towards spontaneous speech synthesis - LM based selection of pronunciation variants

State of the art speech synthesis systems achieve a high overall quality. However, the synthesized speech still lacks naturalness. To make speech synthesis more natural and colloquial we are trying to integrate effects that are observable in spontaneous speech. In a previous paper we introduced a new approach for duration control in speech synthesis that uses the probability of a word in its context to control the local speaking rate within the utterance. This idea is based on the observation that words that are very likely to occur in a given context are pronounced faster than improbable ones. Since probable words are not only pronounced faster but also less accurate we extend this approach by selecting appropriate pronunciation variants to realize the change in the local speaking rate.