Language Identification Accuracy Research Articles

Spoken Language Identification using CNN with Log Mel Spectrogram Features in Indian Context

This study demonstrates a novel application of Log Mel Spectrogram coefficients to image classification via Convolutional Neural Networks (CNN). The acoustic features obtained as log mel spectrogram images are used in this article. Log mel spectrogram pictures, a novel technique, ensure that the system is noise-resistant and free of channel mismatch. The majority of Indian languages from our own dataset were used.With the use of auditory features integrated in CNN, we hope to quickly and accurately detect a language. InceptionV3 and Resnet50 models are also used in this study for performance analysis. When compared to the existing system, these approaches achieved significant improvements in language identification accuracy.

Integration of Phonotactic Features for Language Identification on Code-Switched Speech

In this paper, phoneme sequences are used as language information to perform code-switched language identification (LID). With the one-pass recognition system, the spoken sounds are converted into phonetically arranged sequences of sounds. The acoustic models are robust enough to handle multiple languages when emulating multiple hidden Markov models (HMMs). To determine the phoneme similarity among our target languages, we reported two methods of phoneme mapping. Statistical phoneme-based bigram language models (LM) are integrated into speech decoding to eliminate possible phone mismatches. The supervised support vector machine (SVM) is used to learn to recognize the phonetic information of mixed-language speech based on recognized phone sequences. As the back-end decision is taken by an SVM, the likelihood scores of segments with monolingual phone occurrence are used to classify language identity. The speech corpus was tested on Sepedi and English languages that are often mixed. Our system is evaluated by measuring both the ASR performance and the LID performance separately. The systems have obtained a promising ASR accuracy with data-driven phone merging approach modelled using 16 Gaussian mixtures per state. In code-switched speech and monolingual speech segments respectively, the proposed systems achieved an acceptable ASR and LID accuracy.

Multilingual Speech Corpus in Low-Resource Eastern and Northeastern Indian Languages for Speaker and Language Identification

Research and development of speech technology applications in low-resource languages (LRL) are challenging due to the non-availability of proper speech corpus. Especially, for most of the Indian languages, the amount and type of data found in different digital sources are sparse and prior works are too few to serve the purpose of large-scale development needs. This paper illustrates the creation process of such an LRL corpus comprising of sixteen rarely studied Eastern and Northeastern (E&NE) Indian languages and presents the data variability with different statistics. Furthermore, several experiments are carried out using the collected LRL corpus to build baseline speaker identification (SID) and language identification (LID) system for acceptance evaluation. For investigating the presence of speaker and language-specific information, spectral features like Mel frequency cepstral coefficients (MFCCs), shifted delta cepstral (SDC), and relative spectral transform-perceptual linear prediction (RASTA-PLP) features are used here. Vector quantization (VQ), Gaussian mixture models (GMMs), support vector machine (SVM), and multilayer perceptron (MLP)-based models are developed to represent the speaker and language-specific information captured through the spectral features. Apart from this, i-vectors, time delay neural networks (TDNN), and recurrent neural network with long short-term memory (LSTM-RNN) method-based SID and LID models are being experimented with to comply with the recent approaches. Performances of the developed systems are analyzed with LRL corpus in terms of SID and LID accuracy. The best SID and LID performances are observed to be 94.49% and 95.69%, respectively, for the baseline systems using LSTM-RNN with MFCC + SDC feature.

Language Recognition using Neural Phone Embeddings and RNNLMs

New advances in Language Identification (LID) using Recurrent Neural Networks (RNNs) and Neural Embeddings have been proposed recently. While their application has been successfully applied at a word level, results at a phoneme level may not be as good because of the greater variability found in phoneme sequences which reduces LID accuracy. Thus, we propose to use phonetic units called “phonegrams” that implicitly include longer-context information and use them to train neural embeddings and RNN language models (RNNLMs). Neural embeddings are used in a pre-processing data phase to reduce the scattering problem produced by the high number of resulting phone-gram units, and, in a second phase, we have used the RNNLMs to obtain the scores of each language in the identification task following a PPRLM structure. Results in terms of Cavg on the KALAKA-3 database show that the use of phone-grams provides up to 14.4% relative improvement over a baseline using only phonemes as features. In addition, our proposed strategy of reducing the number of phone-gram units using neural embeddings contributes to obtain up to 23.0% relative improvement. Finally, fusing the best system with MFCC-based acoustic i-vectors and a traditional PPRLM architecture provides up to 39.3% improvement.

On Hierarchical Text Language-Identification Algorithms

Text on the Internet is written in different languages and scripts that can be divided into different language groups. Most of the errors in language identification occur with similar languages. To improve the performance of short-text language identification, we propose four different levels of hierarchical language identification methods and conducted comparative tests in this paper. The efficiency of the algorithms was evaluated on sentences from 97 languages, and its macro-averaged F1-score reached in four-stage language identification was 0.9799. The experimental results verified that, after script identification, language group identification and similar language group identification, the performance of the language identification algorithm improved with each stage. Notably, the language identification accuracy between similar languages improved substantially. We also investigated how foreign content in a language affects language identification.

Language identification using phase information

The present work investigates the importance of phase in language identification (LID). We have proposed three phase based features for the language recognition task. In this work, auto-regressive model with scale factor error augmentation have been used for better representation of phase based features. We have developed three group delay based systems, namely, normal group delay based system, auto-regressive model group delay based system and auto-regressive group delay with scale factor augmentation based system. As mel-frequency cepstral coefficients (MFCCs) are extracted from the magnitude of the Fourier transform, we have combined this MFCC-based system with our phase-based systems to exploit the complete information contained in a speech signal. In this work, we have used IITKGP-MLILSC speech database and OGI Multi-language Telephone Speech (OGI-MLTS) corpus for our experiments. We have used Gaussian mixture models for building the language models. From the experimental results it is observed that the LID accuracy obtained from our proposed phase based features is comparable with MFCC features. We have also observed some performance improvement in the LID accuracy on combining the proposed phase-based systems with the state of the art MFCC-based system.

Parametric representation of excitation source information for language identification

In this work, the linear prediction (LP) residual signal has been parameterized to capture the excitation source information for language identification (LID) study. LP residual signal has been processed at three different levels: sub-segmental, segmental and supra-segmental levels to demonstrate different aspects of language-specific excitation source information. Proposed excitation source features have been evaluated on 27 Indian languages from Indian Institute of Technology Kharagpur-Multi Lingual Indian Language Speech Corpus (IITKGP-MLILSC), Oregon Graduate Institute Multi-Language Telephone-based Speech (OGI-MLTS) and National Institute of Standards and Technology Language Recognition Evaluation (NIST LRE) 2011 corpora. LID systems were developed using Gaussian mixture model (GMM) and i-vector based approaches. Experimental results have shown that segmental level parametric features provide better identification accuracy (62%), compared to sub-segmental (40%) and supra-segmental level (34%) features. Excitation source features obtained from three levels show distinct language-specific evidence. Therefore, the scores from all three levels are combined to obtain the complete excitation source information for the LID task. LID performances achieved from both the excitation source and vocal tract system are compared. Finally, the scores obtained by processing the vocal tract and excitation source features are combined to achieve better improvement in LID accuracy. The best recognition accuracies obtained from stage-IV integrated LID systems I, II and III are 69%, 70% and 72% respectively.

Spoken language recognition-a step toward multilinguality in speech processing

Automatic recognition of spoken languages has become an important feature in a variety of speech-enabled multilingual applications which, besides accuracy, also demand for efficient and linguistically scalable algorithms. This paper deals with a particularly successful approach based on phonotactic-acoustic features and presents systems for language identification as well as for unknown-language rejection. An architecture with multipath decoding, improved phonotactic models using binary-tree structures, and acoustic pronunciation models serve as a framework for experiments and discussion on these two tasks. In particular, language identification accuracy on a telephone-speech task (NIST'95 evaluation) in six and nine languages is presented together with results from a perceptual experiment carried out with human listeners. The performance of language rejection based on phonotactic modeling combined with a monolingual LVCSR system in the domain of broadcast news transcription is also reported. Besides yielding state-of-the-art performance, the described systems are computationally inexpensive and easily extensible (scalable) to new languages without the need for linguistic experts.