Global TIMIT Learner Treebank English

Item Name: Global TIMIT Learner Treebank English
Author(s): Huan Luan, Yanhong Wang, Hui Feng, Wenchao He, Xiaoyan Hu, Yu Wu, Jiahong Yuan, Mark Liberman
LDC Catalog No.: LDC2020S09
ISBN: 1-58563-946-X
ISLRN: 678-780-575-672-7
Release Date: October 15, 2020
Member Year(s): 2020
DCMI Type(s): Sound, Text
Sample Type: pcm
Sample Rate: 16000
Data Source(s): microphone speech
Application(s): speech recognition
Language(s): English
Language ID(s): eng
License(s): LDC User Agreement for Non-Members
Online Documentation: LDC2020S09 Documents
Licensing Instructions: Subscription & Standard Members, and Non-Members
Citation: Luan, Huan, et al. Global TIMIT Learner Treebank English LDC2020S09. Web Download. Philadelphia: Linguistic Data Consortium, 2020.
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Global TIMIT Learner Treebank English was developed by the Linguistic Data Consortium and LAIX Inc. and consists of approximately 24 hours of L1 and L2 English read speech and transcripts.

The Global TIMIT project aimed to create a series of corpora in a variety of languages with a similar set of key features as in the original TIMIT Acoustic-Phonetic Continuous Speech Corpus (LDC93S1) which was designed for acoustic-phonetic studies and for the development and evaluation of automatic speech recognition systems. Specifically, these features include:

  • A large number of fluently-read sentences, containing a representative sample of phonetic, lexical, syntactic, semantic, and pragmatic patterns
  • A relatively large number of speakers
  • Time-aligned lexical and phonetic transcription of all utterances
  • Some sentences read by all speakers, others read by a few speakers, and others read by just one speaker


Global TIMIT Learner Treebank English consists of two separate data sets of 50 speakers reading 120 sentences from Treebank-3 (LDC99T42). Among the 120 sentences, 20 sentences were read by all speakers, 40 sentences were read by 10 speakers, and 60 sentences were read by one speaker, for a total of 3220 sentence types.

L1 English Treebank was recorded at the University of Pennsylvania, USA; participants were 25 female and 25 male native American English speakers. L2 English Treebank was recorded at LAIX Inc., Shanghai, China. L2 speakers (25 female, 25 male) were Chinese learners of English considered fluent and who had passed specified standards on English assessment tests.

All speech data are presented as 16kHz, 16-bit flac compressed wav files. Each file has accompanying phone and word segmentation files, sentence parse trees, and Praat TextGrid files.


The authors acknowledge the generous support of the University of Pennsylvania's Office of the Vice Provost for Global Initiatives (PennGlobal) through its Penn China Research and Engagement Fund, and School of Arts and Sciences through its Global Engagement Fund as well as the Linguistic Data Consortium.


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