RKrogh 

Interface-based TTS abstraction for .NET. Provides ITtsEngine, SSML detection/preprocessing, and audio utilities with zero dependencies.

Core abstractions for speech-to-text with pluggable providers

Windows SAPI (System.Speech) engine for TextToVoice. Native SSML support with automatic namespace normalization.

SherpaOnnx engine for TextToVoice. Embedded ONNX inference for cross-platform offline synthesis with no external processes.

ElevenLabs engine for TextToVoice. High-quality cloud-based TTS via the ElevenLabs REST API.

Piper TTS engine for TextToVoice. Cross-platform offline synthesis via the Piper executable.

NAudio-based microphone capture for VoiceToText (Windows)

Whisper.net speech-to-text provider for VoiceToText

Vosk speech-to-text provider for VoiceToText