Learning dependency translation models as collections of finite state head transducers
Paper · 2000 · Hiyan Alsawi, Srinivas Bangalore and Shona Douglas
Summary
The paper addresses statistical machine translation without hand-written rules or semantic annotation, modelling translation as paired dependency structures. Its central device is the weighted head transducer. This finite-state machine begins at a chosen head symbol and reads input and writes output outward on both sides. That makes it strictly more expressive than conventional left-to-right transducers; for example, it can reverse strings of any length with a finite number of states. A dependency transduction model is a set of such transducers applied recursively, each mapping a source headword and its dependents to a target headword and its dependents. A dynamic programming search finds the lowest-cost derivation.
Training requires only unannotated sentence pairs:
- correlation statistics guide a search for hierarchical alignments;
- transducer transitions are extracted from those alignments;
- weights are maximum-likelihood log probabilities.
The method was tested on spoken-language data for English-to-Spanish (ATIS) and English-to-Japanese (AT&T operator calls). The trained models clearly beat word-for-word baselines and decode faster than real time, which matters for speech translation.
Key points
- Head transducers trained here use only input and output positions in {-1, 0, 1}. Unlike left-to-right FSTs, they allow unbounded movement with finitely many states.
- English-to-Spanish (ATIS transcriptions) used 13,966 training bitexts of up to 20 words and 1,185 held-out test bitexts. The model e2s scored 73.3/75.0 (simple/translation accuracy, %) overall, against 45.2/46.9 for the sww baseline.
- English-to-Japanese (customer–operator telephone utterances) used 12,226 training and 3,253 test bitexts, evaluated on Japanese characters. The model e2j scored 66.4/70.1 overall, against 37.2/42.8 for the jww baseline.
- Vocabularies were only a few thousand words, and utterances averaged 7.3 words. The authors note that broader domains such as newspaper text remain untested.
- On a 300MHz processor, decoding takes less time than speaking the utterance. The authors also claim better efficiency and more natural phrase decomposition than the IBM models (Brown et al.).
Fields, topics and concepts
📚 Shelves 2The field of science this work belongs to (OpenAlex fields).Computer Science · 16,667 worksArtificial Intelligence · 16,194 works
🧭 Topics 1Research subjects and languages the work is about.Machine translation · 1,087 works
Cite
Cite as Hiyan Alsawi, Srinivas Bangalore and Shona Douglas. 2000. Learning dependency translation models as collections of finite state head transducers. Computational Linguistics.
@article{alsawi2000learning,
title = {{Learning dependency translation models as collections of finite state head transducers}},
author = {Hiyan Alsawi, Srinivas Bangalore and Shona Douglas},
journal = {Computational Linguistics},
year = {2000},
url = {https://aclanthology.org/J00-1004/}
}References
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