arXiv:2507.22612v1 Announce Type: cross Abstract: Speech-to-text alignment is a critical component of neural text to-speech (TTS) models. Autoregressive TTS models typically use an attention mechanism to learn these alignments on-line. However, these alignments tend to be brittle and often fail to generalize to long utterances and out-of-domain text, leading to missing or repeating words. Most non-autoregressive end to-end TTS models rely on durations extracted from external sources, using additional duration models for alignment. In this paper, we propose a novel duration prediction framework that can give compromising phoneme-level duration distribution with given text. In our experiments, the proposed duration model has more precise prediction and condition adaptation ability compared to previous baseline models. Numerically, it has roughly a 11.3 percents immprovement on alignment accuracy, and makes the performance of zero-shot TTS models more robust to the mismatch between prompt audio and input audio.