We introduce the Treebank of Learner English (TLE), the first publicly
available syntactic treebank for English as a Second Language (ESL). The TLE
provides manually annotated POS tags and Universal Dependency (UD) trees for
5,124 sentences from the Cambridge First Certificate in English (FCE) corpus.
The UD annotations are tied to a pre-existing error annotation of the FCE,
whereby full syntactic analyses are provided for both the original and error
corrected versions of each sentence. Further on, we delineate ESL annotation
guidelines that allow for consistent syntactic treatment of ungrammatical
English. Finally, we benchmark POS tagging and dependency parsing performance
on the TLE dataset and measure the effect of grammatical errors on parsing
accuracy. We envision the treebank to support a wide range of linguistic and
computational research on second language acquisition as well as automatic
processing of ungrammatical language. The treebank is available at
universaldependencies.org. The annotation manual used in this project and a
graphical query engine are available at esltreebank.org.

TLE 是第一个提供公开的英语为第二语言的句法树库，它为来自剑桥英语第一证书（FCE）语料库的 5,124 个句子提供了手动注释的 POS 标签和通用依赖（UD）树。该树库可用于支持广泛的第二语言习得领域和自动处理不流畅语言的计算机研究。