Papers › Frustratingly Easy Label Projection for Cross-lingual Transfer

Frustratingly Easy Label Projection for Cross-lingual Transfer

28 Nov 2022arXiv:2211.15613archive 2025-07-28

Yang Chen, Chao Jiang, Alan Ritter, Wei Xu

Translating training data into many languages has emerged as a practical solution for improving cross-lingual transfer. For tasks that involve span-level annotations, such as information extraction or question answering, an additional label projection step is required to map annotated spans onto the translated texts. Recently, a few efforts have utilized a simple mark-then-translate method to jointly perform translation and projection by inserting special markers around the labeled spans in the original sentence. However, as far as we are aware, no empirical analysis has been conducted on how this approach compares to traditional annotation projection based on word alignment. In this paper, we present an extensive empirical study across 57 languages and three tasks (QA, NER, and Event Extraction) to evaluate the effectiveness and limitations of both methods, filling an important gap in the literature. Experimental results show that our optimized version of mark-then-translate, which we call EasyProject, is easily applied to many languages and works surprisingly well, outperforming the more complex word alignment-based methods. We analyze several key factors that affect the end-task performance, and show EasyProject works well because it can accurately preserve label span boundaries after translation. We will publicly release all our code and data.

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convert_examples_to_features edchengg/easyproject/ner/utils_ner.py official repository unverified MIT (permissive) · cec6338a46a61ed0 · report
halfen edchengg/easyproject/ner/decode_marker_conll.py official repository unverified MIT (permissive) · 35340916993999b5 · report
judge_if_Chinese_and_Japanese_char edchengg/easyproject/ner/decode_marker_conll.py official repository unverified MIT (permissive) · 4b1d1aa43106f57a · report
judge_if_Chinese_char edchengg/easyproject/ner/decode_marker_conll.py official repository unverified MIT (permissive) · 81d48856b7ce8168 · report
read_examples_from_file edchengg/easyproject/ner/utils_ner.py official repository unverified MIT (permissive) · c80e5c9a8ef905bf · report
read_examples_from_file edchengg/easyproject/ner/process_conll.py official repository unverified MIT (permissive) · ba009de5b2cadce3 · report
read_examples_from_file edchengg/easyproject/ner/process_wikiann.py official repository unverified MIT (permissive) · d6c77bb6d749edd4 · report
read_examples_from_file_flexible edchengg/easyproject/ner/utils_ner.py official repository unverified MIT (permissive) · cad5b48757653160 · report
save_pickle edchengg/easyproject/ner/process_conll.py official repository unverified MIT (permissive) · 4809235f7dd5aba7 · report

Tasks

Cross-Lingual NERCross-Lingual TransferEvent ExtractionNERQuestion AnsweringSentenceTranslationWord Alignment

Results from the paper archive 2025-07-28

TaskDatasetModelMetricValueRank at snapshotLeaderboardReport
Cross-Lingual NER MasakhaNER2.0 EasyProject Akan/Twi 65.3 #1 of 2 Archive leaderboard report
Cross-Lingual NER MasakhaNER2.0 EasyProject Bambara 45.8 #1 of 2 Archive leaderboard report
Cross-Lingual NER MasakhaNER2.0 EasyProject Chichewa 75.3 #1 of 2 Archive leaderboard report
Cross-Lingual NER MasakhaNER2.0 EasyProject Ewe 78.5 #1 of 2 Archive leaderboard report
Cross-Lingual NER MasakhaNER2.0 EasyProject Fon 61.4 #1 of 2 Archive leaderboard report
Cross-Lingual NER MasakhaNER2.0 EasyProject Hausa 72.2 #1 of 2 Archive leaderboard report
Cross-Lingual NER MasakhaNER2.0 EasyProject Igbo 65.6 #1 of 2 Archive leaderboard report
Cross-Lingual NER MasakhaNER2.0 EasyProject Kinyarwanda 71.0 #1 of 2 Archive leaderboard report
Cross-Lingual NER MasakhaNER2.0 EasyProject Kiswahili 83.6 #1 of 2 Archive leaderboard report
Cross-Lingual NER MasakhaNER2.0 EasyProject Luganda 76.7 #1 of 2 Archive leaderboard report
Cross-Lingual NER MasakhaNER2.0 EasyProject Luo 50.2 #1 of 2 Archive leaderboard report
Cross-Lingual NER MasakhaNER2.0 EasyProject Mossi 53.1 #1 of 2 Archive leaderboard report
Cross-Lingual NER MasakhaNER2.0 EasyProject Setswana 74.0 #1 of 2 Archive leaderboard report
Cross-Lingual NER MasakhaNER2.0 EasyProject Wolof 58.9 #1 of 2 Archive leaderboard report
Cross-Lingual NER MasakhaNER2.0 EasyProject Yoruba 36.8 #1 of 2 Archive leaderboard report
Cross-Lingual NER MasakhaNER2.0 EasyProject chiShona 55.9 #1 of 2 Archive leaderboard report
Cross-Lingual NER MasakhaNER2.0 EasyProject isiXhosa 71.1 #1 of 2 Archive leaderboard report
Cross-Lingual NER MasakhaNER2.0 EasyProject isiZulu 73.0 #1 of 2 Archive leaderboard report

Ranks are positions in the archive's leaderboards as they stood at the 2025-07-28 snapshot. Results published since then are not among these rows, so a rank here is not a current standing.

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