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CTC-DID: CTC-Based Arabic dialect identification for streaming applications

Muhammad Umar Farooq, Oscar Saz

TL;DR

This work reimagines Arabic dialect identification as an ASR-like, limited-vocabulary task by optimizing a CTC-based model that outputs dialect tags sequentially over time. Using a self-supervised encoder (mHuBERT) plus a transformer head, and training with repeated dialect labels via LAH or ASR-derived counts, the method enables streaming and robust performance on short utterances. The approach outperforms Whisper and ECAPA-TDNN on ADI-17 and achieves zero-shot superiority on Casablanca, demonstrating strong generalization under limited data. Its streaming-friendly design and potential for extension to code-switching and other ID tasks make it practically impactful for real-time dialect and related identification applications.

Abstract

This paper proposes a Dialect Identification (DID) approach inspired by the Connectionist Temporal Classification (CTC) loss function as used in Automatic Speech Recognition (ASR). CTC-DID frames the dialect identification task as a limited-vocabulary ASR system, where dialect tags are treated as a sequence of labels for a given utterance. For training, the repetition of dialect tags in transcriptions is estimated either using a proposed Language-Agnostic Heuristic (LAH) approach or a pre-trained ASR model. The method is evaluated on the low-resource Arabic Dialect Identification (ADI) task, with experimental results demonstrating that an SSL-based CTC-DID model, trained on a limited dataset, outperforms both fine-tuned Whisper and ECAPA-TDNN models. Notably, CTC-DID also surpasses these models in zero-shot evaluation on the Casablanca dataset. The proposed approach is found to be more robust to shorter utterances and is shown to be easily adaptable for streaming, real-time applications, with minimal performance degradation.

CTC-DID: CTC-Based Arabic dialect identification for streaming applications

TL;DR

This work reimagines Arabic dialect identification as an ASR-like, limited-vocabulary task by optimizing a CTC-based model that outputs dialect tags sequentially over time. Using a self-supervised encoder (mHuBERT) plus a transformer head, and training with repeated dialect labels via LAH or ASR-derived counts, the method enables streaming and robust performance on short utterances. The approach outperforms Whisper and ECAPA-TDNN on ADI-17 and achieves zero-shot superiority on Casablanca, demonstrating strong generalization under limited data. Its streaming-friendly design and potential for extension to code-switching and other ID tasks make it practically impactful for real-time dialect and related identification applications.

Abstract

This paper proposes a Dialect Identification (DID) approach inspired by the Connectionist Temporal Classification (CTC) loss function as used in Automatic Speech Recognition (ASR). CTC-DID frames the dialect identification task as a limited-vocabulary ASR system, where dialect tags are treated as a sequence of labels for a given utterance. For training, the repetition of dialect tags in transcriptions is estimated either using a proposed Language-Agnostic Heuristic (LAH) approach or a pre-trained ASR model. The method is evaluated on the low-resource Arabic Dialect Identification (ADI) task, with experimental results demonstrating that an SSL-based CTC-DID model, trained on a limited dataset, outperforms both fine-tuned Whisper and ECAPA-TDNN models. Notably, CTC-DID also surpasses these models in zero-shot evaluation on the Casablanca dataset. The proposed approach is found to be more robust to shorter utterances and is shown to be easily adaptable for streaming, real-time applications, with minimal performance degradation.
Paper Structure (11 sections, 3 figures, 2 tables, 1 algorithm)

This paper contains 11 sections, 3 figures, 2 tables, 1 algorithm.

Figures (3)

  • Figure 1: Flow of the proposed dialect identification approach. The components within the shaded grey box represent modules that can either be frozen or fine-tuned during training. The green box highlights the inference pipeline.
  • Figure 2: The relationship between relative degradation in F1 score when only the utterances of length $\leq Duration$ are evaluated through the best model.
  • Figure 3: Effect on F1-score with different chunk sizes and context windows for streaming inference