Building the Cantonese Wordnet Joanna Ut-Seong Sio Luis Morgado da Costa Palacky University Nanyang Technological University Olomouc, the Czech Republic Singapore [email protected] [email protected] Abstract Chinese languages (Handel, 2015). The term ‘topolects’ is coined by Mair (1991) to refer to Chinese dialects or, more generally, to speech This paper reports on the development varieties where the label of either ‘language’ or of the Cantonese Wordnet, a new wordnet ‘dialect’ would be controversial. Nevertheless, project based on Hong Kong Cantonese. It for the purpose of this paper, we will continue is built using the expansion approach, lever- to use the term ‘Chinese’ to refer to this fam- aging on the existing Chinese Open Wordnet, ily of languages and the term ‘dialects’ to refer and the Princeton Wordnet’s semantic hierar- to its variants while being fully aware of the chy. The main goal of our project was to pro- complexity involved. duce a high quality, human-curated resource – There are seven most recognised dialectal and this paper reports on the initial efforts and groups: Mandarin (or Northern Chinese), Xi- steady progress of our building method. It is ang, Gan, Wu, Yue, Hakka and Min (Han- our belief that the lexical data made available del, 2015). Norman (1988) classifies the tradi- by this wordnet, including Jyutping romaniza- tional seven dialectal groups into three larger tion, will be useful for a variety of future uses, groups: Northern (Mandarin), Central (Wu, including many language processing tasks and Gan, and Xiang) and Southern (Hakka, Yue, linguistic research on Cantonese and its inter- and Min). Cantonese belongs to Yue, the actions with other Chinese dialects. Southern group, and it is often used as an 1 Introduction alternative name for this whole group. The variety this Cantonese Wordnet is based on is 1.1 Chinese and its Dialects Hong Kong Cantonese. Hong Kong Cantonese Chinese is generally treated as one language is often considered a prestige variety due to with many dialects for both cultural and po- its association with the prosperous southern litical reasons. The dialects are spoken by peo- provinces as well as with the Cantonese cul- ple who mostly identify as a single nationality ture of films and popular music. with a shared cultural history. Linguistically speaking, this unifying view is problematic as 1.2 Project Motivation the dialects are not always mutually intelli- A few wordnets exist for Chinese languages. gible. Chinese is, more accurately, a family These efforts include some work on Pre-Qin of genetically-related languages most proba- Ancient Chinese (Zhang et al., 2017), Mid- bly descended from a form of late Old Chinese dle Ancient Chinese (Zhang et al., 2014), as dating from the Han Dynasty or slightly ear- well as multiple wordnets for Mandarin Chi- lier (with the possible exception of Min (Han- nese, namely: the Sinica Bilingual Ontolog- del, 2015)). Various dialects, including Can- ical Wordnet (Huang, 2003; Huang et al., tonese, had also been importing grammati- 2004, BOW), the Southeast University Chi- cal elements from neighboring languages (Yue- nese WordNet (Xu et al., 2008, SEW), the Chi- Hashimoto, 1991), creating dialectal varia- nese WordNet (Huang et al., 2010, CWN) and tions that are more than the sum of language- the Chinese Open Wordnet (Wang and Bond, internal changes. An arguably less confus- 2013, COW). The Chinese Open Wordnet is ing term ‘Sinitic’ is often used to refer to the the best and most recent effort to produce a high quality wordnet for Mandarin Chinese, tonese and Mandarin vocabulary ranges from learning from previous analogous experiences 30-50%. Ouyang (1993, 23) estimates that and developed alongside a sense-tagged corpus about 1/3 of the lexical items used in reg- (Tan and Bond, 2014; Wang and Bond, 2014; ular Cantonese speech is not found in Man- Seah and Bond, 2014). darin. To give an example for a very common Unfortunately, scholarly efforts often seem item,‘umbrella’ is yǔsǎn ⾬傘 in Mandarin but to forgo Cantonese, as there is a chronic ab- ze1 遮 in Cantonese. In cases where they share sence of digital resources to study and pro- the same lexical item, the item is always pro- cess this important Chinese dialect. To further nounced differently in the two dialects. For ex- stress this problem, it is important to note that ample, ‘teacher’ ⽼師 is pronounced as lǎoshī the significant differences between Mandarin, in Mandarin and lou5si1 in Cantonese. The for which there are plenty of resources, and vowels of the first syllables in each case are dif- Cantonese make the idea of using Mandarin ferent, and the onsets of the second syllables resources to process Cantonese fairly useless. are also different, not to mention tonal differ- It was this chronic absence of Cantonese dig- ences. Note that the romanization system is ital resources that ultimately fed our motiva- different here as well. Mandarin uses pīnyīn, tions to build the Cantonese Wordnet. Our which is based exclusively upon the pronun- motivation spawns from our belief that Can- ciation of the Beijing dialect. In Cantonese, tonese should have plenty of open, compu- Jyutping is used, a point we will come back to tational tractable and linguistically rich re- later. sources, such as wordnets and corpora, that In the existing Mandarin Chinese Wordnet, support scholarly work, as well as this lan- simplified characters are used. The simplified guage’s maintenance and preservation – simi- script, adopted in 1949, aims to alleviate some lar to what happens with Mandarin Chinese. of the difficulty associated with use of the tra- We would like our Cantonese Wordnet to ditional script, as a measure to eradicate illit- support many Natural Language Processing eracy. In Hong Kong, Macau and Taiwan, the tasks, such as speech recognition, word sense traditional script is used, though in the former disambiguation, machine translation or infor- two, changes are happening rapidly since their mation retrieval. And, at the same time, to return to China in 1997 and 1999, respectively. also support the study of purely linguistic re- Cantonese is primarily a spoken variant. A search topics, such as lexical semantics, tonal lot of lexical items, excluding those shared patterns, verb subcategorization, etc. with Mandarin, do not have fixed agreed upon characters, these are often called ‘character- 2 Cantonese: an Overview less’ words. It is not always easy to determine Cantonese is the second most widely known which character to use as there is no standard- Chinese dialect after Mandarin (Matthews ization. In some cases, multiple options are and Yip, 1994). It is spoken in Guang- available, while in some other cases, no op- dong Province, Guangxi Province, the Spe- tions are available. We will pick up on this cial Administrative Regions of Hong Kong and issue in Section 4.3. Macau, as well as diaspora communities in 2.1 Jyutping Romanization System North America, Australia, Malaysia, Singa- Pīnyīn is the official romanization system of pore, etc. According to Ethnologue,1 there are Mandarin Chinese or Pǔtōnghuà (lit. ‘com- 73 million Cantonese speakers worldwide. But mon speech’). And since Mandarin Chi- despite the large number of speakers, credi- nese/Pǔtōnghuà and Cantonese have different ble online resources on Cantonese, free or oth- phonological systems, a different romanization erwise, are limited, especially in comparison system is needed for Cantonese. Many ro- with Mandarin. manization systems exists for Cantonese (e.g., There is a considerable lexical overlap be- Jyutping, S.L. Wong, Sidney Lau, Yale, the tween Cantonese and Mandarin. Snow (2004, Government System, etc.) (Cheng and Tang, 49) mentions that the difference between Can- 2016). We adopt the Jyutping system, 粵 1https://www.ethnologue.com/language/yue 拼, for the Cantonese Wordnet. Jyutping was developed by the Linguistic Society of Hong a lemma, both its Jyutping representation and Kong (LSHK) in 1993. Its formal name is The its graph (character) are needed. For example, Linguistic Society of Hong Kong Cantonese sing1 can mean ‘to rise’ 升 or ‘star’ 星. With- Romanization Scheme.2 Since its inception, out the character, it is ambiguous. it is used widely in academic papers as well as social media. 3 Methodology Cantonese syllables contain onset and rime. The rime can be further divided into the nu- There are two main methods to build wordnets cleus and coda. The lists of possible onset, (Vossen, 1998). The first method is known as nucleus and coda in Jyutping are shown in the ‘expansion’ approach, where the structure Table 1. /m/ and /ng/ are syllabic nasals, of another wordnet is used as ‘pivot’, and the meaning they can appear on their own to form main work is essentially a translation effort – a syllable. Kataoka and Lee (2008) provide conserving the structure of the pivot wordnet the correspondence between Jyutping, the In- and translating nodes of the hierarchy. The ternational Phonetic symbol (IPA) and other Princeton Wordnet (Fellbaum, 1998, PWN) Cantonese romanization systems. is, by far, the most frequently used ‘pivot’ for projects that employ this approach. The Jyutping phonemes second method is known as the ‘merge’ ap- Onset b, p, m, f, d, t, n, l, g, k, ng, proach. This is usually a slower method, since h, gw, kw, w, z, c, s, j no pivot structure is assumed, but it ensures Nucleus aa, i, u, e, o, yu,oe, a, eo a higher degree of freedom to more carefully Coda p, t, k, m, n, ng, i, u model the structure of the wordnet based on the language in question, without depending Table 1: Jyutping Syllable Struture on pre-assumed semantic relations. One of the immediate benefits of this approach is the abil- In Jyutping, tones are expressed numeri- ity to add new concepts that are not part of cally, using numbers 1 to 6.