Source Language Effecton Translating Korean Honorifics
Kyonghee Paik1 , Kiyonori Ohtake1 , Francis Bond2 ,Kazuhide Yamamoto1,3
1

ATR Spoken Language Translation Research Laboratories
2-2-2 Hikaridai “Keihanna Science City”, Kyoto 619-0288 JAPAN{kyonghee.paik, kiyonori.ohtake}@atr.co.jp
2

Nippon Telegraph and Telephone Corporation
2-4 Hikaridai, “Keihanna Science City”, Kyoto 619-0237 JAPANbond@cslab.kecl.ntt.co.jp
3

Nagaoka University of Technology
1603-1 Kamitomioka, Nagaoka City, Niigata 940-2188 JAPAN
yamamoto@fw.ipsj.or.jp

Abstract. This paper investigates honorific phenomena on two variantsof Korean translation corpus, based on translations from Japanese andEnglish. One surprising result is how different the corpora were, evenafter normalizing orthographic differences. Translations are dependent
not just meaning, but also on the structure of the source text.

1Introduction

This paper investigates the effect of source language on honorifics in translations
using two variants of a Korean translation corpus. The original corpus was compiled from Japanese-English parallel sentences collected from phrase books forJapanese traveling abroad. The corpora used for this research consist of 324,616
Korean sentences. Half of the Korean sentences (162,308 sentences: henceforth,KJ ) were translated from Japanese and the other half (henceforth, KE ) havebeen translated from English sentences which match the Japanese.
Although the two Korean corpora are generally equivalent in meaning, they
have different characteristics, since they were translated from such different languages as English and Japanese. We show that the differences between Englishand Japanese lead to different results in the Korean translation, even though theoriginal source texts were matching Japanese-English translation pairs.
Our ultimate goal is to find the differences in translations by comparing twovariants with different source texts in order to improve the quality of machinetranslation. So far such comparison has not been extensively studied.

2

Honorifics in Japanese and Korean

Korean is an honorific language with an extremely systematic grammaticalization. A sentence cannot be uttered without the speaker’s knowledge of theirsocial relationship to the addressee and referent considering social status, age,kinship, familiarity and so on. Otherwise, the utterance may sound rude, inappropriate, or even awkward (Sohn 1999, p.16).
Japanese honorifics are also expressed by various forms according to the degree of honor or respect, addressee, or situation. Like Korean, Japanese canmake nouns and verbs honorific using different lexical items or adding prefixes
and suffixes. For verbal constructions, Japanese uses o/go- V ni naru “do” (subject honorific) and o/go -V suru “do” (addressee honorific (humble)) as well as
two different speech levels of verb endings: da (plain) desu (polite) (Kaiser etal 2001). Korean uses verbal suffixes -si to make subject honorifics and -sup to
make addressee honorifics, along with six different speech levels.
There are many mismatches between the two systems from Japanese to Korean. For example, Japanese beautifies nouns o- or go- before nouns like o-saifu“wallet”, o-sio “salt”, go-tsugo “convenience”. However, Korean does not have acorresponding system to this. As for verb honorifics at speech levels, Korean has
six different levels whereas Japanese has only two levels. This will cause mistakes
in machine translation between the two languages.

3Analysis of our corpora

We compared sentences using the perl module String::Similarity (Lehman2000). It returns a similarity score based on the edit distance (the number ofcharacters that need to be deleted, added or substituted to change one string
into another), normalized to give a score between 0 and 1 (see Meyers (1986) fora fuller description). Two completely different strings have a score of zero, while
two identical strings have a score of one. There were 136,529 sentences. Their
distribution is given in Table 1. As there were many identical sentences in eachcorpus, we give the distribution over both all sentences and unique sentences.
Less than 2% of the sentences were the same in both corpora. Most sentenceswere reasonably similar (0.4–0.8). Very few sentences were identical (less than4%) and even fewer were totally dissimilar (less than 0.1%). There were someminor orthographic differences. When they were resolved, only 8.3% of the sentences were identical. To put this in perspective, Culy and Riehemann (2003)discuss the fact that there is considerable variation in translations from exactly
the same source text. It is impossible to explicitly compare their results for two
reasons: (1) they are looking at more literary texts, where the translators certainly were aware of the previous translations and trying to differentiate theirown; (2) they do not quantify the differences using the same measure as us.
We took one percent of the unique sentences for each of 9 similarity bands
from 0.1–0.2 to 0.9–1.0 for more detailed evaluation. The sample size was proportional to the number of sentences in each band — so the samples are small
at each extreme and large in the center. We evaluated 1,360 randomly chosen
sample sentences and all 58 sentences of the least similar band (0.0–0.1).
Since our corpora deals with the topics related to various travel situations,
there are numerous sentences inquiring and trying to get information which areTable 1. Distribution of the sentences by similarity score
Similarity Score
0-0.1 0.1-0.2 0.2-0.3 0.3-0.4 0.4-0.5 0.5-0.6 0.6-0.7 0.7-0.8 0.8-0.9 0.9-1.0 Total
Sall
100 1,910 11,006 23,126 33,755 34,888 28,083 17,400 7,693 4,347 162,308
Suniq
58 1,243 7,876 19,351 29,053 30,149 24,382 14,946 6,434 3,037 136,529

uttered using polite or deferential forms of interrogatives in most cases. The
different use of adjectives, adverbs, or their phrases are also found all throughdifferent similarity scores. These phenomena form a useful source for learning
lexical paraphrasing rules for example-based paraphrasing.
We found strikingly different distributions in KJ and KE with regard tohonorifics, which are shown in Table 2 and discussed below.
Table 2. Honorific differences between KJ and KE
Similarity Score
0.0-0.1 0.1-0.2 0.2-0.3 0.3-0.4 0.4-0.5 0.5-0.6 0.6-0.7 0.7-0.8 0.8-0.9 0.9-1.0
Samples
58
1278
192
290
300
243
149
64
30
Honorific (KJ ) 4
1
10
16
82
101
76
32
112
Honorific (KE ) 20815
20
32
31
920
Loan word (KJ ) 005
161415760000
711911300
Loan word (KE ) 0The differences shown in Table 2 mainly arise from the fact that KJ tends
to use more deferential honorifics whereas the KE tends to use more polite honorifics, although this distinction is not made in either English or Japanese. Evenso, the source language affects the degree or level of honorifics. For example, K E
tend to use polite speech levels like - -yo where as KJ tend to use deferen
tial forms like -   -(su)pnika for asking questions. This systematic difference
makes these two corpora a suitable source for the automatic acquisition of paraphrasing rules. The difference in honorific use is strongly shown in the bands
from 0.4 to 0.9. In general, KJ used more honorifics than KE overall, and theeffect was to make it a more natural collection of travel phrases.
As we have seen, the source language has a large effect on the translation,although we have focused on honorifics in this paper. This suggests that theoptimal translation strategy may be different between language pairs. In particular, a system translating between Japanese and Korean needs to put less effort
into lexical and syntactic choice, and more into the use of honorifics. A systemgoing between English and Korean has a much harder task, and must consider
lexical and syntactic choice, zero pronoun resolution in addition to the use ofhonorifics.
Differences in honorific usage appeared to be fairly predictable between thetwo corpora, and lead to the hope that a paraphrasing module can be used tofix the honorific levels after translation itself occurs, along the lines suggested
by Ohtake and Yamamoto (2001).
Another interesting difference was in the distribution of borrowed words orforeign words from languages other than Chinese. We expected that more loan
words would be used in KE because most loan words come from English. However, according to Table 2 the result is the opposite. Further, the loan words
translated from Japanese, were in general more natural (73%) than those translated from English (50%). After examining the source corpora of KJ , we foundthat many “Katakana” loan words are used in the Japanese corpus. Almost all of
the Katakana words are translated into loan words in Korean. In contrast, all theEnglish words are equally foreign, so for any word, there is little pressure for it
to be translated into a loan word, rather than into native Korean. When English
words were translated as loan words, they tended to be poor literal translations.

4Conclusion and Further WorkWe investigated two variants of a Korean translation corpus, based on translations from Japanese and English. We have shown that the source language text
has a large influence on the target text. One surprising result is how different
the corpora were, even after normalizing orthographic differences. In practice,translations are dependent not just on meaning, but also on the structure of
the source text. We find that the expressions on honorifics which were examinedusing similarity scores are reliable resources for paraphrasing.
Based on these findings, we intend to examine whether we can automaticallyextract grammatical, semantic and lexical paraphrases by comparing corpora
using similarity scores.

Acknowledgement
This research was supported in part by the Telecommunications Advancement
Organization of Japan.

References
Culy, C. & S. Z. Riehemann: 2003, ‘The limits of N-gram translation evaluation metrics’, in Proceedings of MT Summit IX , New Orleans.
Kaiser, Stefan, Y. Ichikawa, N. Kobayashi & H. Yamamoto: 2001, Japanese: A Comprehensive Grammar , Routledge.
Lehmann, Marc: 2000, ‘String::Similarity’, Perl Module (cpan.org), (v0.02).
Myers, Eugene: 1986, ‘An O(ND) difference algorithm and its variations’, Algorithmica,
1(2): 251–266.
Ohtake, Kiyonori & Kazuhide Yamamoto: 2001, ‘Paraphrasing honorifics’, in NLPRS2001 , Tokyo, pp. 13–20.
Sohn, Ho-Min: 1999, The Korean Language, Cambridge Language Surveys, Cambridge
University Press.