Early builds of the MRTK supported Speech to Text but not the other way around. Many developers wanted a way to use Text to Speech, so Jared created a component and contributed it to the toolkit. This component is multi-threaded, supports multiple voices, integrates with Unity’s audio engine, and supports spatialization. It still exists in MRTK today. (Article, Source)
Mixed Reality Analytics
A reference implementation for how to capture gaze data spatially over time.