Item Name: NTIMIT
Author(s): William M. Fisher, George R. Doddington, Kathleen M. Goudie-Marshall, Charles Jankowski, Ashok Kalyanswamy, Sara Basson, Judith Spitz
LDC Catalog No.: LDC93S2
ISBN: 1-58563-010-1
ISLRN: 032-224-820-254-0
DOI: https://doi.org/10.35111/0zg2-nn38
Member Year(s): 1993
DCMI Type(s): Sound
Sample Type: 1-channel pcm
Sample Rate: 16000
Data Source(s): telephone speech
Application(s): speech recognition
Language(s): English
Language ID(s): eng
License(s): LDC User Agreement for Non-Members
Online Documentation: LDC93S2 Documents
Licensing Instructions: Subscription & Standard Members, and Non-Members
Citation: Fisher, William M., et al. NTIMIT LDC93S2. Web Download. Philadelphia: Linguistic Data Consortium, 1993.
Related Works: View


NTIMIT was developed by the NYNEX Science and Technology Speech Communication Group to provide a telephone bandwidth adjunct to TIMIT (LDC93S1), which consists of approximately five hours of English speech along with time-aligned transcriptions. NYNEX retains full copyright on the corpus and all associated materials.

NTIMIT was collected by transmitting all 6,300 original TIMIT recordings through a telephone handset and over various channels in the NYNEX telephone network and redigitizing them. The recordings were transmitted through ten Local Access and Transport Areas, half of which required the use of long-distance carriers.


In order to calibrate the transmission characteristics of the various channels, stationary 1 kHz and frequency-sweeping tones were also recorded for each of the transmission channels.

The re-recorded waveforms were time-aligned with the original TIMIT waveforms so that the TIMIT time-aligned transcriptions can be used with NTIMIT as well. Like the TIMIT files, the NTIMIT are single channel, 16-bit, 16kHz. In addition to the documentation included with this release, see Jankowski et al., "NTIMIT: A Phonetically Balanced, Continuous Speech, Telephone Bandwidth Speech Database," Proc. ICASSP-90, April 1990.


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(02/08/2016) All sphere files were updated to flac, and the corpus was converted from a media release to a web download. Documentation was edited to reflect these changes. Note that some documentation may still refer to the corpus as being relased on CD-ROM and containing sphere files.

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