RATS Language Identification

Item Name: RATS Language Identification
Author(s): David Graff, Xiaoyi Ma, Stephanie Strassel, Kevin Walker, Karen Jones
LDC Catalog No.: LDC2018S10
ISBN: 1-58563-852-8
ISLRN: 190-505-311-077-0
DOI: https://doi.org/10.35111/xjdn-0g13
Release Date: July 16, 2018
Member Year(s): 2018
DCMI Type(s): Sound
Sample Type: pcm
Sample Rate: 16000
Data Source(s): telephone conversations
Project(s): RATS
Application(s): language identification
Language(s): South Levantine Arabic, North Levantine Arabic, Persian, Dari, Pushto, Urdu
Language ID(s): ajp, apc, fas, prs, pus, urd
License(s): LDC User Agreement for Non-Members
Online Documentation: LDC2018S10 Documents
Licensing Instructions: Subscription & Standard Members, and Non-Members
Citation: Graff, David, et al. RATS Language Identification LDC2018S10. Web Download. Philadelphia: Linguistic Data Consortium, 2018.
Related Works: View


RATS Language Identification was developed by the Linguistic Data Consortium (LDC) and is comprised of approximately 600 hours of Levantine Arabic, Farsi, Dari, Pashto and Urdu conversational telephone speech with annotation of speech segments. The audio was retransmitted over eight channels, making 5,400 hours of total audio. The corpus was created to provide training, development and initial test sets for the Language Identification (LID) task in the DARPA RATS (Robust Automatic Transcription of Speech) program.

The goal of the RATS program was to develop human language technology systems capable of performing speech detection, language identification, speaker identification and keyword spotting on the severely degraded audio signals that are typical of various radio communication channels, especially those employing various types of handheld portable transceiver systems. To support that goal, LDC assembled a system for the transmission, reception and digital capture of audio data that allowed a single source audio signal to be distributed and recorded over eight distinct transceiver configurations simultaneously. Those configurations included three frequencies -- high, very high and ultra high -- variously combined with amplitude modulation, frequency hopping spread spectrum, narrow-band frequency modulation, single-side-band or wide-band frequency modulation. Annotations on the clear source audio signal, e.g., time boundaries for the duration of speech activity, were projected onto the corresponding eight channels recorded from the radio receivers.


The source audio consists of conversational telephone speech recordings from: (1) conversational telephone speech (CTS) recordings, taken either from previous LDC CTS corpora, or from CTS data collected specifically for the RATS program from Levantine Arabic, Pashto, Urdu, Farsi and Dari native speakers; and (2) portions of VOA broadcast news recordings, taken from data used in the 2009 NIST Language Recognition Evaluation. The 2009 LRE Test Set is available from LDC as LDC2014S06.

CTS recordings were audited by annotators who listened to short segments and determined whether the audio was in the target language. Annotations on the audio files include start time, end time, speech activity detection (SAD) label, SAD provenance, language ID and LID provenance.

All audio files are presented as single-channel, 16-bit PCM, 16000 samples per second; lossless FLAC compression is used on all files; when uncompressed, the files have typical "MS-WAV" (RIFF) file headers.

The data is divided for use as training, initial development set, and initial evaluation set.


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This material is based upon work supported by the Defense Advanced Research Projects Agency (DARPA) under Contract No. D10PC20016. The content does not necessarily reflect the position or the policy of the Government, and no official endorsement should be inferred.

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