languages Article Focus Prosody Varies by Phrase-Initial Tones in Seoul Korean: Production, Perception, and Automatic Classification Yong-cheol Lee 1,* and Sunghye Cho 2,* 1 Department of English Language and Literature, Cheongju University, Cheongju 28503, Korea 2 Linguistic Data Consortium, University of Pennsylvania, Philadelphia, PA 19104, USA * Correspondence: [email protected] (Y.-c.L.); [email protected] (S.C.) Received: 22 September 2020; Accepted: 11 November 2020; Published: 18 November 2020 Abstract: Production and perception experiments were conducted to examine whether focus prosody varies by phrase-initial tones in Seoul Korean. We also trained an automatic classifier to locate prosodic focus within a sentence. Overall, focus prosody in Seoul Korean was weak and confusing in production, and poorly identified in perception. However, Seoul Korean’s focus prosody differed between phrase-initial low and high tones. The low tone group induced a smaller pitch increase by focus than the high tone group. The low tone group was also subject to a greater degree of confusion, although both tone groups showed some degree of confusion spanning the entire phrase as a focus effect. The identification rate was, therefore, approximately half in the low tone group (23.5%) compared to the high tone group (40%). In machine classification, the high tone group was also more accurately identified (high: 86% vs. low: 68%) when trained separately, and the machine’s general performance when the two tone groups were trained together was much superior to the human’s (machine: 65% vs. human: 32%). Although the focus prosody in Seoul Korean was weak and confusing, the identification rate of focus was higher under certain circumstances, which avers that focus prosody can vary within a single language. Keywords: focus prosody; Seoul Korean; tonal contrast; production; human perception; machine perception 1. Introduction Focus highlights a particular element in a sentence (Bolinger 1972; Xu and Xu 2005). It is normally modulated by prosodic prominence to emphasize its importance in communication. However, prosodic prominence marking focus varies according to each language’s prosodic system. For example, in English, prominence is marked by a post-lexical pitch accent on the head (i.e., a stressed syllable) of a word (Beckman and Pierrehumbert 1986; Cohan 2000; Jun 2011; Ladd 1996). Additionally, prosodic focus in American English is well identified by a machine classifier with a high accuracy (92%) (Cho et al. 2019). In Mandarin Chinese, it is also cued by the head of a word, but is distinctively characterized by the tone shape of individual lexical tones (Lee et al. 2016; Liu 2009; Yuan 2004). However, in Seoul Korean (SK), focus is expressed through prosodic phrasing in which a new phrase boundary is inserted before the focused word and prominence occurs throughout the entire focused word (Jun 2011; Lee 2012). Based on Jun’s (Jun 2005, 2014) prosodic typology, English and Mandarin Chinese belong to head-prominence languages. However, SK is labeled as an edge-prominence language because prominence is realized by marking the edge of a prosodic constituent. In order to understand the details of the current study, we first briefly overview SK’s prosodic system. We then provide a detailed description of how prosodic focus is manifested in SK. Finally, we present our research goals. Languages 2020, 5, 64; doi:10.3390/languages5040064 www.mdpi.com/journal/languages Languages 2020, 5, 64 2 of 19 Languages 2020, 5, x FOR PEER REVIEW 2 of 19 SK has neither lexical stress nor lexical pitch accents (Ueyama and Jun 1998; Song 2005). Instead, in defaultSK prosodichas neither phrasing, lexical eachstress content nor lexical word pitch usually accents forms (Ueyama a small prosodicand Jun 1998; unit called Song an2005). Accentual Instead, Phrasein default (AP) (prosodicJun 1998 )phrasing, that is tonally each markedcontent atword the post-lexical usually forms level. a Thesmall typical prosodic melody unit of called an AP an isAccentual either LH-LH Phrase or HH-LH,(AP) (Jun depending 1998) that onis tonally an AP-initial marked onset at the segment. post-lexical The level. AP-initial The typical tone is melody high whenof an the AP initial is either onset LH-LH has the or HH-LH, feature [ +dependingaspirated /ontense], an AP-initial while it isonset low segment. when the The initial AP-initial onset has tone theis featurehigh when [ aspirated the initial/tense]. onset Intermediate has the feature H-L [+aspi tonesrated/tense], (either one orwhile both) it is are low omitted when fromthe initial APs thatonset − containhas the less feature than [ four−aspirated/tense]. syllables, resulting Intermediate in several H-L tonal tones patterns: (either one L-H, or L-LH,both) are LH-H, omitted H-H, from H-LH, APs HH-H.that contain Regarding less the than AP four melody syllables, of SK, resulting recent studies in several (Cho andtonal Lee patterns: 2016; Cho L-H, 2017 L-LH,) showed LH-H, that H-H, AP’s H- pitchLH, targetHH-H. is Regarding much higher the when AP melody it begins of withSK, recent a high-tone studies inducing (Cho and segment Lee 2016; and Cho the high2017) pitch showed is retainedthat AP’s toward pitch thetarget final is much syllable higher of an when AP. 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Description 0241 Ɂ \textglotstopvari LATIN CAPITAL LETTER GLOTTAL STOP 0242 ɂ \textglotstopvarii LATIN SMALL LETTER GLOTTAL STOP 0243 Ƀ \textbarcapitalb LATIN CAPITAL LETTER B WITH STROKE 0244 Ʉ \textbarcapitalu LATIN CAPITAL LETTER U BAR 0245 Ʌ \textturnedcapitalv LATIN CAPITAL LETTER TURNED V 0246 Ɇ \textstrokecapitale LATIN CAPITAL LETTER E WITH STROKE 0247 ɇ \textstrokee LATIN SMALL LETTER E WITH STROKE USV Symbol Macro(s) Description 0248 Ɉ \textbarcapitalj LATIN CAPITAL LETTER J WITH STROKE 0249 0266 ɉ ɦ \textbarj\m{h} LATIN SMALLLATIN LETTERSMALL LETTER J WITH STROKE H WITH HOOK 024A Ɋ \texthtcapitalq\texthookabove{h} LATIN CAPITAL LETTER SMALL Q WITH HOOK TAIL \texthth 024B ɋ \texthtq LATIN SMALL LETTER Q WITH HOOK TAIL 0267 ɧ \texthookabove{\textheng} LATIN SMALL LETTER HENG WITH HOOK 024C Ɍ \textbarcapitalr LATIN CAPITAL LETTER R WITH STROKE \texththeng 024D ɍ \textbarr LATIN SMALL LETTER R WITH STROKE 0268 ɨ \B{i} LATIN SMALL LETTER I WITH STROKE 024E Ɏ \textbarcapitaly\textbari LATIN CAPITAL LETTER Y WITH STROKE 024F 0269 ɏ ɩ \textbary\m{i} LATIN SMALLLATIN LETTERSMALL LETTER Y WITH IOTA STROKE 0250 ɐ \textturna\textiota LATIN SMALL LETTER TURNED A \textiotalatin 0251 ɑ \textscripta LATIN SMALL LETTER ALPHA \textniiota 0252 ɒ \textturnscripta LATIN SMALL LETTER TURNED ALPHA 026A ɪ \textsci LATIN LETTER SMALL CAPITAL I 0253 ɓ \m{b} LATIN SMALL LETTER B WITH HOOK 026B ɫ \textltilde LATIN SMALL LETTER L WITH MIDDLE TILDE \m{b} 026C ɬ \texthtb\textbeltl LATIN SMALL LETTER L WITH BELT 026D ɭ \textbhook\textrethookbelow{l} LATIN SMALL LETTER L WITH RETROFLEX HOOK 0254 ɔ \m{o}\textrtaill LATIN SMALL LETTER OPEN O Figure 1. Mean pitch values of all speakers by the length of the target words. The x-axis shows syllable Figure026E 1. Meanɮ \textopenopitch\textlyoghlig values of all speakers by the length of the target words.LATIN The SMALL x-axis LETTER shows LEZH syllable positionspositions in in the the target \textoopentarget\textOlyoghlig sentences, sentences, and and the the y-axis y-axis shows shows the the mean mean pitch pitch values. values. The The first first three three syllables syllables 0255 026F ɕ ɯ \textctc\textturnmtopic LATIN SMALLLATIN LETTERSMALL LETTER C WITH TURNED CURL M areare for for/i.t /i.te.nɕe.nnɯ/n/‘now- ‘now-TOPIC’,’, and and the the last last four four syllables syllables are are for fo/rmal.ha.se.jo /mal.ha.se.jo// ‘say’ ‘say’ in in the the carrier carrier 0256 0270 ɖ ɰ \M{d}\textturnmrleg LATIN SMALLLATIN LETTERSMALL LETTER D WITH TURNED TAIL M WITH LONG LEG sentencesentence/i.d /i.dʑe.nɯne.n n ________ mal.ha.se.jomal.ha.se.jo// ‘Now‘Now saysay _____.’, _____.’, and and the the syllables syllables in in the the middle middle (inside (inside the the 0271 ɱ \textrtaild\m{m} 1 LATIN SMALL LETTER M WITH HOOK dashed lines) are the target words. Modified1 from Cho and Lee(2016). dashed lines) are\textdtail the\textltailm target words. Modified from Cho and Lee (2016). 0257 ɗ \m{d} LATIN SMALL LETTER D WITH HOOK Figure02722 depictsɲ SK’s\m{j} focus realizations when a focused word startsLATIN with SMALL a LETTER low-tone N WITH LEFT inducing HOOK Figure 2 depicts\texthtd SK’s\textltailn focus realizations when a focused word starts with a low-tone inducing segment. Focus conditions\textdhook\textnhookleft were produced in an experimental setting in which six native speakers of segment.0258 Focusɘ conditions\textreve were produced in an experimental settingLATIN in SMALL which LETTER six REVERSED native E speakers of SK read stimuli0273 inɳ isolation\m{n} for broad focus and produced the same stimuliLATIN SMALL in a LETTER Q&A N WITH dialogue RETROFLEX HOOK for SK0259 read stimuliə in \schwaisolation\textrtailn for broad focus and produced the sameLATIN stimuli SMALL LETTER in SCHWA a Q&A dialogue for discourse-new focus.