Both repositories are maintained by the same team and contain the same model files.
DataoceanAI1 is the newly created enterprise organization account, while DataoceanAI is kept to avoid breaking existing user download scripts and links.
Please do not regard either repository as an unofficial copy or unauthorized redistribution.
Dolphin-CN-Dialect is a multi-dialect ASR model developed by Dataocean AI and Tsinghua University, with a strong focus on Chinese dialect recognition and real-world deployment scenarios. Compared with the previous Dolphin series, Dolphin-CN-Dialect introduces significant improvements in tokenizer design, dialect-balanced training, streaming capability, hotword biasing, and deployment efficiency.
The model supports Mandarin Chinese and 22 Chinese dialects, while also maintaining multilingual ASR capability inherited from Dolphin. Dolphin-CN-Dialect supports both streaming and non-streaming inference, enabling practical deployment in latency-sensitive applications such as real-time transcription and industrial speech recognition systems.
Approach
Dolphin-CN-Dialect is built upon the Dolphin architecture and follows a joint CTC-Attention framework with:
Encoder: E-Branchformer
Decoder: Transformer Decoder
Training Objective: Joint CTC + Attention loss
Compared to Dolphin, Dolphin-CN-Dialect introduces several important improvements:
Temperature-based data sampling for balancing standard Mandarin and low-resource dialects
Redesigned tokenizer with:
character-level modeling for Chinese
BPE-based subword modeling for English
extensible dialect tokens
Streaming ASR support
Hotword-biased decoding, including:
encoder-level contextual biasing
prompt-based decoder biasing
Experimental results show that Dolphin-CN-Dialect achieves:
38% improvement in dialect recognition accuracy
16.3% relative CER reduction over Dolphin
Competitive performance with recent large-scale ASR systems while maintaining a smaller model size
Currently, Dolphin-CN-Dialect provides multiple model sizes optimized for different deployment scenarios.
Model
Parameters
Hotwords
base.cn
0.1 B
❌
base.cn.streaming
0.1 B
❌
small.cn
0.4 B
Encoder-biased Hotwords
small.cn.streaming
0.4 B
Encoder-biased Hotwords
small.cn.prompt
0.4 B
Prompt-based Hotwords
Hotword Biasing
Dolphin-CN-Dialect supports two hotword biasing approaches.
Encoder-Level Contextual Biasing
Supports both streaming and non-streaming models
Integrates contextual embeddings into encoder representations
Efficient adaptation without retraining the full model
Prompt-Based Hotword Biasing
Designed for non-streaming models
Injects hotwords directly into decoder prompts
Particularly effective for long-tail and rare phrases
Experimental results show significant reductions in hotword error rates while maintaining strong overall ASR performance.
Supported Languages and Dialects
Dolphin-CN-Dialect primarily focuses on:
Mandarin Chinese
22 Chinese dialects
Regional accented Mandarin
Supported dialects include:
Sichuan
Wu
Minnan
Shanghai
Gansu
Guangdong
Wenzhou
Hunan
Anhui
Henan
Fujian
Hebei
Liaoning
Shaanxi
Tianjin
and more
For the complete language and dialect list, see languages.md.
Supported Devices
Device Type
Support Status
CUDA
✅Supported
MPS (Apple)
✅Supported
Ascend NPU (Huawei)
✅Supported
CPU
✅Supported
To run Dolphin on Ascend NPU, you need to install the corresponding torch_npu package and configure the environment ASCEND_RT_VISIBLE_DEVICES. The tested configuration is: CANN==8.0.1, torch==2.2.0, torch_npu==2.2.0. With this setup, the model has been verified to run inference correctly on the Ascend NPU.
Usage
Command-line usage
shell
1dolphin audio.wav
23# Download model and specify the model path4dolphin audio.wav --model small.cn --model_dir /data/models/dolphin/
56# Specify language and region7dolphin audio.wav --model small.cn --model_dir /data/models/dolphin/ --lang_sym "zh" --region_sym "CN"89# Specify the hotwords file with Encoder-biased method10dolphin audio.wav --model small.cn --model_dir /data/models/dolphin/ --hotword_list_path hotwords.txt --use_deep_biasing true1112# Using prompt-based model13dolphin audio.wav --model small.cn.prompt --model_dir /data/models/dolphin/ --hotword_list_path hotwords.txt --use_prompt_hotword true --use_two_stage_filter true14