Endangered language generally has low-resource characteristics, as an immaterial cultural resource that cannot be renewed. Automatic speech recognition (ASR) is an effective means to protect this language. However, for low-resource language, native speakers are few and labeled corpora are insufficient. ASR, thus, suffers deficiencies including high speaker dependence and over fitting, which greatly harms the accuracy of recognition. To tackle the deficiencies, the paper puts forward an approach of audiovisual speech recognition (AVSR) based on LSTM-Transformer. The approach introduces visual modality information including lip movements to reduce the dependence of acoustic models on speakers and the quantity of data. Specifically, the new approach, through the fusion of audio and visual information, enhances the expression of speakers’ feature space, thus achieving the speaker adaptation that is difficult in a single modality. The approach also includes experiments on speaker dependence and evaluates to what extent audiovisual fusion is dependent on speakers. Experimental results show that the CER of AVSR is 16.9% lower than those of traditional models (optimal performance scenario), and 11.8% lower than that for lip reading. The accuracy for recognizing phonemes, especially finals, improves substantially. For recognizing initials, the accuracy improves for affricates and fricatives where the lip movements are obvious and deteriorates for stops where the lip movements are not obvious. In AVSR, the generalization onto different speakers is also better than in a single modality and the CER can drop by as much as 17.2%. Therefore, AVSR is of great significance in studying the protection and preservation of endangered languages through AI.

As an endangered language, Tujia language is a non-renewable intangible cultural resource. Automatic speech recognition (ASR) uses artificial intelligence technology to facilitate manually label Tujia language, which is an effective means to protect this language. However, due to the fact that Tujia language has few native speakers, few labeled corpus, and much noise in the corpus. The acoustic models thus suffer from over fitting and lowe noise immunity, which seriously harms the accuracy of recognition. To tackle the deficiencies, an approach of audio-visual speech recognition (AVSR) based on Transformer-CTC is proposed, which reduces the dependence of acoustic models on noise and the quantity of data by introducing visual modality in-formation including lip movements. Specifically, the new approach enhances the expression of speakers’ feature space through the fusion of audio and visual information, thus solving the problem of less available information for single modality. Experiment results show that the optimal CER of AVSR is 8.2% lower than that of traditional models, and 11.8% lower than that for lip reading. The proposed AVSR tackles the issue of low accuracy in recognizing endangered languages. Therefore, AVSR is of great significance in studying the protection and preservation of endangered languages through AI.