What are Text-to-Speech Models?
Text-to-speech (TTS) models are specialized AI systems that convert written text into natural-sounding human speech. Using advanced deep learning architectures and large-scale voice datasets, they transform text input into audio output with proper intonation, emotion, and pronunciation. This technology enables developers and creators to add voice capabilities to applications, generate audiobooks, create accessible content, and build conversational AI systems. Cost-effective TTS models democratize access to professional voice synthesis, making it feasible for startups, developers, and enterprises to integrate high-quality speech generation into their products without prohibitive costs.
FunAudioLLM/CosyVoice2-0.5B
CosyVoice 2 is a streaming speech synthesis model based on a large language model with a unified streaming/non-streaming framework. The 0.5B parameter model achieves ultra-low latency of 150ms in streaming mode while maintaining synthesis quality. It reduces pronunciation error rates by 30%-50% compared to v1.0, improves MOS scores from 5.4 to 5.53, and supports fine-grained control over emotions and dialects across Chinese (including Cantonese, Sichuan, Shanghainese, Tianjin dialects), English, Japanese, and Korean.
FunAudioLLM/CosyVoice2-0.5B: Best Value Ultra-Low Latency TTS
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. At only $7.15 per million UTF-8 bytes on SiliconFlow, it offers exceptional value.
Pros
- Most affordable at $7.15/M UTF-8 bytes on SiliconFlow.
- Ultra-low latency of 150ms in streaming mode.
- 30%-50% reduction in pronunciation error rates.
Cons
- Smaller 0.5B parameter size compared to larger models.
- May have slightly less naturalness than premium models.
Why We Love It
- It delivers professional-grade streaming speech synthesis with emotion control and multilingual support at the industry's most competitive price point, making high-quality TTS accessible to everyone.
IndexTeam/IndexTTS-2
IndexTTS2 is a breakthrough auto-regressive zero-shot TTS model with precise duration control and emotion-timbre disentanglement. It supports explicit token count specification for precise timing and separate control of speaker identity and emotional expression. The model achieves superior performance in word error rate, speaker similarity, and emotional fidelity, with a text-based soft instruction mechanism for intuitive emotion control.
IndexTeam/IndexTTS-2: Premium Features at Budget Pricing
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 at $7.15 per million UTF-8 bytes on SiliconFlow.
Pros
- Same affordable pricing as CosyVoice at $7.15/M UTF-8 bytes on SiliconFlow.
- Precise duration control for video dubbing applications.
- Separate control of timbre and emotion via prompts.
Cons
- May require more complex prompting for optimal results.
- Zero-shot performance varies with prompt quality.
Why We Love It
- It combines advanced features like precise duration control and emotion-timbre disentanglement with budget-friendly pricing, perfect for video dubbing and emotional voice applications.
fishaudio/fish-speech-1.5
Fish Speech V1.5 is a leading open-source TTS model with innovative DualAR architecture featuring dual autoregressive transformer design. Trained on over 300,000 hours of English and Chinese data and 100,000 hours of Japanese, it achieved an ELO score of 1339 in TTS Arena evaluations. The model delivers exceptional accuracy with 3.5% WER and 1.2% CER for English, and 1.3% CER for Chinese characters.
fishaudio/fish-speech-1.5: Top-Ranked Quality at Competitive Pricing
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. At $15 per million UTF-8 bytes on SiliconFlow, it offers exceptional quality-to-price ratio, making it ideal for projects requiring top-tier accuracy and naturalness without premium pricing.
Pros
- Top-ranked performance with ELO score of 1339.
- Exceptional accuracy: 3.5% WER, 1.2% CER for English.
- Trained on 300,000+ hours of multilingual data.
Cons
- Higher cost compared to CosyVoice2 and IndexTTS-2.
- Limited to three primary languages (EN, CN, JP).
Why We Love It
- It delivers arena-leading quality with exceptional accuracy and naturalness at competitive pricing, perfect for applications where speech quality is paramount but budget constraints exist.
TTS Model Comparison
In this table, we compare 2025's most cost-effective text-to-speech models, each offering unique value propositions. FunAudioLLM/CosyVoice2-0.5B provides the best price-to-performance ratio with ultra-low latency and dialect support. IndexTeam/IndexTTS-2 matches that pricing while adding precise duration control for video applications. fishaudio/fish-speech-1.5 delivers top-ranked quality at a competitive price point. This side-by-side comparison helps you select the most economical solution for your specific voice synthesis needs.
| Number | Model | Developer | Subtype | SiliconFlow Pricing | Core Strength |
|---|---|---|---|---|---|
| 1 | FunAudioLLM/CosyVoice2-0.5B | FunAudioLLM | Text-to-Speech | $7.15/M UTF-8 bytes | Best value ultra-low latency |
| 2 | IndexTeam/IndexTTS-2 | IndexTeam | Text-to-Speech | $7.15/M UTF-8 bytes | Duration control & emotion |
| 3 | fishaudio/fish-speech-1.5 | fishaudio | Text-to-Speech | $15/M UTF-8 bytes | Top-ranked quality & accuracy |
Frequently Asked Questions
Our top three picks for the cheapest text-to-speech models in 2025 are FunAudioLLM/CosyVoice2-0.5B, IndexTeam/IndexTTS-2, and fishaudio/fish-speech-1.5. Each of these models stood out for their exceptional cost-effectiveness, performance quality, and unique approach to solving challenges in speech synthesis while maintaining affordable pricing on SiliconFlow.
Our in-depth analysis shows that both FunAudioLLM/CosyVoice2-0.5B and IndexTeam/IndexTTS-2 tie for the most affordable option at just $7.15 per million UTF-8 bytes on SiliconFlow. CosyVoice2-0.5B is the best choice for ultra-low latency streaming applications with multilingual and dialect support, while IndexTTS-2 excels when you need precise duration control for video dubbing or separate emotion and timbre control. For projects requiring the highest quality and accuracy, fishaudio/fish-speech-1.5 at $15 per million UTF-8 bytes offers exceptional value as a top-ranked model.