Gentle

Gentle is a specialized speech processing tool built on the Kaldi speech recognition toolkit, designed specifically for the task of forced alignment. Unlike standard ASR (Automatic Speech Recognition) systems that attempt to transcribe unknown audio, Gentle takes an existing transcript and an audio file to generate precise, word-level time-stamps. Its technical architecture utilizes a weighted finite-state transducer (WFST) approach, creating a dynamic language model based on the provided text. This allows for extremely high precision even in noisy environments or with non-standard accents. In the 2026 market, Gentle remains a critical piece of infrastructure for developers working on automated video captioning, lip-syncing for digital humans, and searchable audio databases. It is uniquely capable of handling 'out-of-vocabulary' segments through its 'mush' model, which attempts to find phonetic matches even when the transcript and audio diverge. As an open-source project, it provides a high-performance, local-first alternative to costly cloud-based alignment APIs, making it the preferred choice for privacy-conscious enterprise workflows and high-volume media processing pipelines.