BOLT CTS CALLFRIEND CALLHOME Egyptian Arabic Audio
| Item Name: | BOLT CTS CALLFRIEND CALLHOME Egyptian Arabic Audio |
| Author(s): | David Graff, Song Chen, Stephanie Strassel |
| LDC Catalog No.: | LDC2025S09 |
| ISLRN: | 475-316-977-261-3 |
| DOI: | https://doi.org/10.35111/6ah6-a104 |
| Release Date: | October 15, 2025 |
| Member Year(s): | 2025 |
| DCMI Type(s): | Sound |
| Sample Type: | 16-bit |
| Sample Rate: | 8000 |
| Data Source(s): | telephone conversations, telephone speech |
| Project(s): | BOLT |
| Application(s): | cross-lingual information retrieval, information retrieval, machine translation, speaker identification, speech recognition |
| Language(s): | Egyptian Arabic |
| Language ID(s): | arz |
| License(s): |
LDC User Agreement for Non-Members |
| Online Documentation: | LDC2025S09 Documents |
| Licensing Instructions: | Subscription & Standard Members, and Non-Members |
| Citation: | Graff, David, Song Chen, and Stephanie Strassel. BOLT CTS CALLFRIEND CALLHOME Egyptian Arabic Audio LDC2025S09. Web Download. Philadelphia: Linguistic Data Consortium, 2025. |
| Related Works: | View |
Introduction
BOLT CTS CALLFRIEND CALLHOME Egyptian Arabic Audio was developed by the Linguistic Data Consortium (LDC) and consists of approximately 116 hours of speech from 274 unscripted telephone conversations between native speakers of the Arabic dialect spoken in Egypt.
The DARPA BOLT (Broad Operational Language Translation) program developed machine translation and information retrieval for less formal genres, focusing particularly on user-generated content. LDC supported the BOLT program by collecting informal data sources -- discussion forums, conversational telephone speech, text messaging and chat -- in Chinese, Egyptian Arabic and English. The material in this release represents the unannotated Egyptian Arabic source conversational telephone speech. The telephone data was subseqently transcribed, translated, and annotated for various tasks in the BOLT program including word alignment, treebanking, and co-reference.
CALLFRIEND and CALLHOME were collections of multilingual telephone speech conducted by LDC in support of language identification and speech identification technology development.
Data
Many of the recordings in this corpus (92 calls, approximately 33%) are publicly released for the first time. The remainder (182 recordings, approximately 66%) were previously published in various CALLFRIEND, CALLHOME and HUB5 Arabic datasets.
All calls originated in North America and were placed to locations overseas. Most participants called family members or close friends. Participants spoke on topics of their choice. Conversations lasted up to 30 minutes. Completed calls passed through a human auditing process to verify that the target language was spoken by the participants, to check the quality of the recordings, and to record information about dialect, noise and distortion.
The data is divided into training, development, and evaluation partitions as follows:
| Partition | Audio Files | Total Hours |
| train | 203 | 89.16 |
| dev | 16 | 5.58 |
| eval | 55 | 21.58 |
| total | 274 | 116.32 |
Audio files are presented in FLAC-compressed MS-WAV/RIFF format; they are two-channel, 16-bit sample data (converted from original mu-law samples) at 8000 samples/second. The audio is contained in two interleaved channels per file representing the two independently recorded sides of the telephone conversation.
Samples
Please listen to this speech sample (.flac)
Acknowledgement
This material is based upon work supported by the Defense Advanced Research Projects Agency (DARPA) under Contract No. HR0011-11-C-0145. The content does not necessarily reflect the position or the policy of the Government, and no official endorsement should be inferred.
Updates
No updates at this time.