What is FastSpeech 2?
FastSpeech 2 is a non-autoregressive text-to-speech model developed by Microsoft Research and Zhejiang University, published in 2020. It's the second generation of the FastSpeech architecture and produces high-quality speech at real-time speeds — up to 3× faster than autoregressive models like Tacotron 2.
FastSpeech 2 implementations are released under MIT license, free for commercial use.
Why FastSpeech 2 Is Still Used in 2026
While newer end-to-end models like VITS and XTTS often deliver better quality, FastSpeech 2 remains popular for real-time production TTS where speed and stability matter more than absolute naturalness.
Its explicit control over pitch, duration, and energy makes it the preferred choice for applications requiring fine-grained voice customization.
Key Features and Capabilities
FastSpeech 2 supports non-autoregressive parallel TTS, pitch control (per phoneme), duration control, energy control, multi-speaker training, and HiFi-GAN vocoder integration.
Who Should Use FastSpeech 2?
FastSpeech 2 is built for real-time TTS application developers, voice assistant builders, animation studios needing lip-sync TTS, accessibility tool makers, and game developers.
Top Use Cases
Real-world applications include real-time voice assistants, video game NPC dialogue, animation lip-sync, accessibility readers, IVR phone systems, and live streaming TTS.
Where Can You Run It?
FastSpeech 2 runs on ESPnet, NVIDIA NeMo, Hugging Face Transformers, and various Coqui TTS forks. It runs in real-time on CPU and at 50-100x real-time on GPU.
How to Use FastSpeech 2 (Quick Start)
Easiest via NVIDIA NeMo: pip install nemo_toolkit[tts], then load nvidia/tts_en_fastpitch (FastPitch is the production successor) and nvidia/tts_hifigan for vocoding.
When Should You Choose FastSpeech 2?
Choose FastSpeech 2 when you need real-time TTS with fine-grained voice control. For higher naturalness, use VITS or XTTS v2. For voice cloning, use OpenVoice.
Pricing
FastSpeech 2 is completely free under MIT license.
Pros and Cons
Pros: ✔ MIT license ✔ 3x faster than Tacotron 2 ✔ Pitch/duration/energy control ✔ Real-time on CPU ✔ Stable inference (no failure modes) ✔ Multi-speaker support
Cons: ✘ Less natural than VITS/XTTS ✘ Two-stage (needs vocoder) ✘ Surpassed by newer end-to-end models ✘ Pronunciation guide needed
Final Verdict
FastSpeech 2 is the speed champion for real-time TTS in 2026 — perfect for production voice applications. Discover more TTS options at FreeAPIHub.com.