What are Fastest Lightweight Speech Recognition Models?
Fastest lightweight speech recognition models are specialized AI systems optimized for converting text to natural-sounding speech with minimal latency and computational requirements. Using advanced architectures like autoregressive transformers and streaming synthesis frameworks, they deliver high-quality voice output while maintaining efficiency. This technology allows developers to integrate real-time voice capabilities into applications, from virtual assistants to video dubbing, with unprecedented speed and accuracy. They foster innovation, democratize access to powerful speech synthesis tools, and enable a wide range of applications from mobile apps to large-scale enterprise voice solutions.
FunAudioLLM/CosyVoice2-0.5B
CosyVoice 2 is a streaming speech synthesis model based on a large language model, employing a unified streaming/non-streaming framework design. In streaming mode, the model achieves ultra-low latency of 150ms while maintaining synthesis quality almost identical to that of non-streaming mode. Compared to version 1.0, the pronunciation error rate has been reduced by 30%-50%, the MOS score has improved from 5.4 to 5.53, and fine-grained control over emotions and dialects is supported.
FunAudioLLM/CosyVoice2-0.5B: Ultra-Low Latency Champion
CosyVoice 2 is a streaming speech synthesis model based on a large language model, employing a unified streaming/non-streaming framework design. The model enhances the utilization of the speech token codebook through finite scalar quantization (FSQ), simplifies the text-to-speech language model architecture, and develops a chunk-aware causal streaming matching model that supports different synthesis scenarios. In streaming mode, the model achieves ultra-low latency of 150ms while maintaining synthesis quality almost identical to that of non-streaming mode. Compared to version 1.0, the pronunciation error rate has been reduced by 30%-50%, the MOS score has improved from 5.4 to 5.53, and fine-grained control over emotions and dialects is supported. The model supports Chinese (including dialects: Cantonese, Sichuan dialect, Shanghainese, Tianjin dialect, etc.), English, Japanese, Korean, and supports cross-lingual and mixed-language scenarios. With only 0.5B parameters, this model delivers exceptional efficiency at just $7.15/M UTF-8 bytes on SiliconFlow.
Pros
- Ultra-low latency of 150ms in streaming mode.
- 30%-50% reduction in pronunciation error rate vs v1.0.
- Improved MOS score from 5.4 to 5.53.
Cons
- Smaller model size may limit some advanced features.
- Primarily optimized for streaming scenarios.
Why We Love It
- It delivers industry-leading 150ms latency with exceptional quality, making it perfect for real-time conversational AI and live streaming applications where speed is critical.
fishaudio/fish-speech-1.5
Fish Speech V1.5 is a leading open-source text-to-speech (TTS) model employing an innovative DualAR architecture with dual autoregressive transformer design. It supports multiple languages, with over 300,000 hours of training data for both English and Chinese, and over 100,000 hours for Japanese. The model achieved a word error rate (WER) of 3.5% and a character error rate (CER) of 1.2% for English, and a CER of 1.3% for Chinese characters.
fishaudio/fish-speech-1.5: Multilingual Accuracy Leader
Fish Speech V1.5 is a leading open-source text-to-speech (TTS) model. The model employs an innovative DualAR architecture, featuring a dual autoregressive transformer design. It supports multiple languages, with over 300,000 hours of training data for both English and Chinese, and over 100,000 hours for Japanese. In independent evaluations by TTS Arena, the model performed exceptionally well, with an ELO score of 1339. The model achieved a word error rate (WER) of 3.5% and a character error rate (CER) of 1.2% for English, and a CER of 1.3% for Chinese characters. This exceptional accuracy combined with extensive multilingual training makes it ideal for global applications. Available on SiliconFlow at $15/M UTF-8 bytes.
Pros
- Innovative DualAR dual autoregressive architecture.
- Top ELO score of 1339 in TTS Arena evaluations.
- Exceptional accuracy: 3.5% WER, 1.2% CER for English.
Cons
- Higher pricing at $15/M UTF-8 bytes on SiliconFlow.
- May require more computational resources than smaller models.
Why We Love It
- Its exceptional accuracy metrics and massive multilingual training dataset make it the gold standard for applications demanding the highest quality speech synthesis across languages.
IndexTeam/IndexTTS-2
IndexTTS2 is a breakthrough auto-regressive zero-shot Text-to-Speech (TTS) model designed for precise duration control, critical for applications like video dubbing. It achieves disentanglement between emotional expression and speaker identity, enabling independent control over timbre and emotion via separate prompts. Experimental results show that IndexTTS2 outperforms state-of-the-art zero-shot TTS models in word error rate, speaker similarity, and emotional fidelity.
IndexTeam/IndexTTS-2: Zero-Shot Precision Powerhouse
IndexTTS2 is a breakthrough auto-regressive zero-shot Text-to-Speech (TTS) model designed to address the challenge of precise duration control in large-scale TTS systems, which is a significant limitation in applications like video dubbing. It introduces a novel, general method for speech duration control, supporting two modes: one that explicitly specifies the number of generated tokens for precise duration, and another that generates speech freely in an auto-regressive manner. Furthermore, IndexTTS2 achieves disentanglement between emotional expression and speaker identity, enabling independent control over timbre and emotion via separate prompts. To enhance speech clarity in highly emotional expressions, the model incorporates GPT latent representations and utilizes a novel three-stage training paradigm. To lower the barrier for emotional control, it also features a soft instruction mechanism based on text descriptions, developed by fine-tuning Qwen3, to effectively guide the generation of speech with the desired emotional tone. Experimental results show that IndexTTS2 outperforms state-of-the-art zero-shot TTS models in word error rate, speaker similarity, and emotional fidelity across multiple datasets. Available on SiliconFlow at $7.15/M UTF-8 bytes for both input and output.
Pros
- Breakthrough zero-shot capability with no fine-tuning needed.
- Precise duration control for video dubbing applications.
- Independent control over timbre and emotional expression.
Cons
- More complex architecture may increase inference time.
- Advanced features require understanding of control parameters.
Why We Love It
- Its groundbreaking zero-shot capabilities and precise duration control make it the ultimate choice for professional video dubbing, audiobook production, and any application requiring exact timing and emotional control.
Speech Recognition Model Comparison
In this table, we compare 2025's leading lightweight speech recognition models, each with a unique strength. For ultra-low latency streaming, FunAudioLLM/CosyVoice2-0.5B offers unmatched 150ms response time. For multilingual accuracy, fishaudio/fish-speech-1.5 provides industry-leading error rates. For zero-shot precision control, IndexTeam/IndexTTS-2 delivers professional-grade duration and emotion management. This side-by-side view helps you choose the right tool for your specific speech synthesis needs.
| Number | Model | Developer | Subtype | Pricing (SiliconFlow) | Core Strength |
|---|---|---|---|---|---|
| 1 | FunAudioLLM/CosyVoice2-0.5B | FunAudioLLM | Text-to-Speech | $7.15/M UTF-8 bytes | Ultra-low 150ms latency |
| 2 | fishaudio/fish-speech-1.5 | fishaudio | Text-to-Speech | $15/M UTF-8 bytes | Top accuracy & multilingual |
| 3 | IndexTeam/IndexTTS-2 | IndexTeam | Text-to-Speech | $7.15/M UTF-8 bytes | Zero-shot duration control |
Frequently Asked Questions
Our top three picks for 2025 are FunAudioLLM/CosyVoice2-0.5B, fishaudio/fish-speech-1.5, and IndexTeam/IndexTTS-2. Each of these models stood out for their innovation, performance, and unique approach to solving challenges in fast, lightweight speech synthesis with exceptional quality and efficiency.
Our in-depth analysis shows several leaders for different needs. FunAudioLLM/CosyVoice2-0.5B is the top choice for ultra-low latency applications with its industry-leading 150ms response time, perfect for real-time conversational AI. For applications requiring maximum accuracy across multiple languages, fishaudio/fish-speech-1.5 excels with its 3.5% WER and extensive training data. For professional video dubbing and applications requiring precise timing control, IndexTeam/IndexTTS-2 is the best choice with its breakthrough zero-shot duration control capabilities.