Identify Bilingual Patterns and Phrases from a Bilingual Sentence Pair (2021)

Abstract: This paper presents a method for automatically identifying bilingual grammar patterns and extracting bilingual phrase instances from a given English-Chinese sentence pair. In our approach, the English-Chinese sentence pair is parsed to identify English grammar patterns and Chinese counterparts. The method involves generating translations of each English grammar pattern and calculating translation probability of words from a word-aligned parallel corpora. The results allow us to extract the most probable English-Chinese phrase pairs in the sentence pair. We present a prototype system that applies the method to extract grammar patterns and phrases in parallel sentences. An evaluation on randomly selected examples from a dictionary shows that our approach has reasonably good performance. We use human judge to assess the bilingual phrases generated by our approach. The results have potential to assist language learning and machine translation research.

## introduction verb phrases are prominent components of any sentence. if we can correctly extract english-chinese bilingual grammar patterns and phrases in a bilingual sentence pair, it will be helpful for english and chinese language learners and machine translation systems. these results can be used to demonstrate the synchronous structure of parallel sentences. however, chinese sentence parsing technology is still immature, which leads to difficulties in obtaining grammar patterns and phrases in chinese sentences. there are still many problems with existing chinese parsers. to extract chinese patterns and phrases more accurately, we utilize an english sentence parser which is much more mature than chinese parsing technology to parse english sentences and extract english patterns and phrases. we also utilize some statistical methods to estimate translation probability of word pairs using bilingual corpora. then, we extract chinese patterns and phrases more accurately by finding counterparts of english patterns and phrases with statistical results from bilingual corpora. we present a system that returns bilingual verb patterns and phrases of a bilingual sentence pair. our system identifies phrases in sentences by using the pattern table and translation probability model created in advance. the pattern table created by parsing english sentences and calculating counterparts in bilingual parallel corpus with word alignment. the translation probability model is created by the alignment probability of each english and chinese word pair with consideration of not only the word itself but also related words. at the runtime, our system starts with an english-chinese bilingual sentence pair submitted by the user. the system parses the english sentence and extracts english patterns and phrases, and retrieves the counterpart of the pattern from the table created in advance to be chinese pattern. then, the system extracts the counterpart of words in the english phrase by the probability model created in advance. finally, the system combines the chinese pattern and the counterpart of words in the english phrase to form a chinese phrase. the system can assist language learning or be used to generate training data for machine translation research, especially research related to phrases. the rest of the article is organized as follows. we review the related work in the next section. then we present our method for automatically identifying bilingual phrases from a bilingual sentence pair in section 3. the experiment and an evaluation based on human judgment are described in section 4. finally, we summarize our conclusions in section 5. ## related work machine translation is a time-honored and yet active research area. shifting from the rule-based approach toward data-intensive approach after the seminal paper by @xcite , an increasing number of bilingual corpora have made statistical machine translation more and more feasible. in our work we address an aspect of machine translation is not a direct focus of @xcite . we also consider on more general linguistic class of units in translation where the translation may not be litateral and may need a presentation that reflects the similarity and differences between two languages involved, and the user might be interested in multiple ways (structures) of translating a phrase (e.g., consider the phrase "harmful to the ocean" and its translation). more recent researches concentrate on learning word translation and extracting bilingual word translation pairs from bilingual corpus, and then calculate the degree of mutual relationship between word pairs in parallel sentences, thereby deriving the precise translation @xcite ; @xcite ; @xcite ; @xcite ; @xcite ; moore (2001)). in our system, we focus on identifying patterns and phrases by a patterns table and a word translation model which are created using statistical methods in bilingual corpora with word alignment. in the area of phrase alignment, @xcite proposed a method for verb phrase translation. for specific verb fragments (e.g. make a report to police), automatic alignment is applied to calculate the collocation relationship across two language (e.g. when make and report appear together, report often corresponds to ), then word and phrase correspondences are generated (e.g. make a report to police correspond to ) ,to tally translations and counts. chen et al. (2020) focus on the translation of noun prepositional collocations. using statistical methods to extract translations of nouns and prepositions from bilingual parallel corpora with sentence alignment, and then adjust the translations with additional information of chinese collocations extracted from a chinese corpus. ## methodology we attempt to identify bilingual grammar patterns and phrases in an english-chinese sentence pair using a lexical translation model and bilingual grammar patterns. our identification process is shown in figure 1 . table (section 3.1) (2) create word translation probability model (section 3.2) (3) system runtime -extracting pattern grammar and phrases in sentence pair (section 3.3) figure 1. identification process 3.1 creating bilingual grammar patterns and phrases table in the first stage of the identification process (step (1) in figure 1 ), we extract chinese grammar patterns for each english grammar pattern. for example, the verb "use" has a grammar pattern "use n to inf", our goal is to extract chinese counterparts such as n v and n v for use n to inf . the input to this stage is english-chinese sentence pairs in a word-aligned bilingual parallel corpus. we parse each english sentence into a tree structure to reveal the dependency of words in the sentence and use a recursive approach to extract the grammar pattern and the phrase for each verb in the sentence. then, we extract chinese counterparts of the english grammar pattern in the chinese sentence according to the word alignment, and convert them into chinese grammar patterns according to the english word in english pattern each chinese word corresponds to. for example, for the sentence pair we use computers to solve the problem. and , we extract the english grammar pattern use n to inf and the 33rd conference on computational linguistics and speech processing (rocling 2021) taoyuan, taiwan, october 15-16, 2021. the association for computational linguistics and chinese language processing english phrase use computer to solve problem for the verb use . then, we extract the chinese counterparts and convert it into chinese pattern n v with converting into n and converting into v according to their correspondence to english phrase and pattern. for each english grammar pattern, we compute the frequency of chinese patterns, and filter patterns with high frequency. then, we sort the patterns by counts and by pattern length as shown in the output of this stage is a table which contains sorted chinese patterns for each english grammar pattern. ## evaluation and discussion the purpose of our system is to allow users to retrieve the bilingual patterns and phrases from a bilingual sentences pair. therefore, in this section, we report the results of preliminary evaluations on the extraction of bilingual patterns and phrases. the evaluation process was conducted on a set of bilingual sentence pairs along with their patterns and phrases extracted. ## conclusion and future work many avenues exist for future research and improvement of our system. as we mentioned in section 4.3, lack of bilingual patterns in our table created in advance causes that many phrases cannot be identified. one such avenue is to design methods to expand the amount of the patterns. for example, we can consider collocations calculated in the chinese monolingual corpus which contains a larger amount of sentences, or consider the synonyms of the words in the pattern by using word embedding or dictionaries like wordnet, to generate more bilingual patterns. in summary, we have introduced a method for identifying patterns and phrases that allow users to submit an english-chinese sentence pair and get bilingual patterns and phrases in the sentence pair. the method involves parsing english sentences and extracting counterparts of english patterns and phrases by using a bilingual pattern table and word translation probability model created in advance. the result of the evaluations show that our method is highly accurate.