ACOUSTIC ANALYSIS OF LEXICAL TONES INCONTEMPORARY STANDARD SLOVENIAN

Peter Jurgec

CASTL, University of Tromsø, N-9037 Tromsø, Norwaypeter.jurgec@hum.uit.no

ABSTRACT

The present investigation into acoustic properties oftones in Slovenian addresses vowel duration, inten-sity and fundamental frequency. Although no statis-tical differences were found with respect to vowelduration and intensity, the two lexical tones (orpitch-accents) differed highly significantly in termsof fundamental frequency. Results from the presentinvestigation differ greatly from what has been pre-viously reported. Roughly, the two lexical classesdiffer on the basis of tone on the stressed and on thefinal syllable. In the first lexical class, tone is Lowon the stressed syllable and High on the final. In thesecond lexical class, the situation is the reverse; thestressed vowel is High in tone while the final sylla-ble is Low.

Keywords: Acoustic phonetics, tones, pitch-accent,Slovenian.

1. INTRODUCTION

Historically, it has been established that Slovenianhas two lexical tones, or pitch-accents, termed acuteand circumflex. The tones are obligatory in somedialects but optional in the standard language. Thestress is an independent of tone in Slovenian, in-dicated by duration [9], vowel quality, spectral tilt[4, 6] and other characteristics, e.g. phonation, cf.[5]. Also, in the non-tonal dialects, stress is markedprimarily by a rise in fundamental frequency. — Asthis investigation is not about phonological proper-ties of the tones in Slovenian, the existence of thetwo lexical classes shall not be questioned.

Although Slovenian tones have been investigatedacoustically since the 1930’s, the results of the ma-jority of studies were inconclusive, often contradic-tory and generally not representative. Studies sofar limited the scope of analysis to fundamental fre-quency. Although duration was mentioned, it wasnot considered systematically [9].

The first acoustic characterization of Sloveniantones based on actual measurements can be traced to[1]. It was not until two decades later, that a properacoustic investigation was conducted [12]. Vodušek

recorded a limited number of tokens and investi-gated speakers of different dialectal background,chiefly linguists. He found two different realizationsof both tones, dependent on the background (dialect)of the informant. A feature common to both variantsis a general Low of the acute tone and a general Highof the circumflex tone (stressed vowels only). How-ever, the author also notes that tones may be realizedover the stressed and the post-tonic syllable, and thatmonosyllables are distinctive in some of the exam-ined dialects.

Toporišic [11] sumarized his findings in a similarmanner: High vs. Low play a decisive role in Slove-nian tones. Based on a much larger corpus of ma-terial but only one speaker, he concluded that bothtones differ in f0 of the stressed and the first post-tonic vowel. In acutes, f0 is Low on the stressedvowel, and High on the post-tonic; in circumlexesthe opposite is true. In the final position of theprosodic word, the post-tonic syllable is omitted,such that acute is realized as Low tone, and circum-flex as High.

Neweklowsky [8] analyzed tone in Carinthian di-alects. He also found significant differences in f0

(as well as duration). Roughly, f0 peak was foundto be the most indicative of both tones, acute havingthe peak on the post-tonic while circumflex havingit on the tonic syllable.

Srebot Rejec [9] investigated both duration andf0, and compiled an extensive corpus of sentencesfrom three male speakers from Ljubljana. With re-gards to prosody, she concludes the following: (i)quantity is no longer distinctive in standard Slove-nian, (ii) tone is marginally, but still significantlydistinctive, although probably not in the final sylla-ble [10], (iii) tones are typically realized as contours.The tones are ideally realized with a peak in f0 atabout two thirds of the duration of the stressed vowel(Class I) or at the end of the post-tonic syllable. Thedomain of tone is a foot consisting of two syllables,or a single syllable in the case of final stress. SrebotRejec’s analysis is phonetically the most accurate sofar. Similar to Neweklowsky, she took three pointsof measurement, in the beginning, middle and endof the vowel. Although more recent sources indi-

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cate progressive loss of tone in Slovenian dialects([7], Vera Smole and Roberto Dapit, p.c.), it is stillbelieved that tonal Slovenian is widely spoken. Pre-liminary results of a perceptual study by the authorshow that tones are perceived well above the chancelevels by the native speakers, contrary to what wasreported by Šuštaršic and Tivadar [13].

In this paper, we try to fill in the gaps in acousticsof Slovenian tones. Three acoustic parameters areinvestigated: fundamental frequency, duration andintensity.

2. METHOD

In order to properly observe tonal phenomena, seg-mental influences, sentence intonation and speakervariability should be minimized from the outset. Ina controlled experiment such as this, the preparedlist of words should be compiled carefully. It isknown that non-vocalic segments influence f0, dura-tion and intensity. In the present investigation, min-imal pairs in tone were used to minimize these vari-ables. Sixteen minimal pairs of mono- to trisylla-bles were selected from available dictionaries, a fewof the pairs being morphologically related. The fol-lowing consonant and vowel patterns were observed:CV.CV as a basic tamplate, CVC.CV and CV.CVCas templates with closed syllables, monosyllableCVC and tri-syllables CV.CV.CV. The complete listof words with both tones includes the following min-imal pairs: 1 mono-syllable, 12 di-syllables (7 ofwhich only have open syllables) and 3 tri-syllables.All words have word-initial stress. Based on the pre-vious findings (see Sec. 1.), pre-tonic syllables werenot analyzed.

The words were then put in frame sentences, us-ing original contexts of the selected words, based onthe text corpus Nova beseda [3]. The sentences wererandomized and put into a Power Point presentationwhich was later read by the subjects.

Next, the subjects were selected. Eight speak-ers from central Slovenia, all residents of Ljubl-jana, some originally form different parts of LowerCarniola (2), Upper Carniola (1) and Carinthia (1).All were educated past high school, four of them fe-male and four male. Median age at the time of theexperiment was 38 years. Two male speakers werelater excluded form the analysis because it was es-tablished that they did not seem to speak a tonal va-riety of Slovenian; their minimal pairs did not dif-fer significantly. Consequently, only the tones ofsix speakers (four females, two males) are acknowl-edged. This may cause a typical frequency bias,such that average F0 would be higher than other-wise. However, it is not the absolute values that are

at question here, but relative pitch contours.The subjects were instructed first to read the sen-

tences that appeared on the computer screen. Thesewere cues for contextualizing relevant words (min-imal pairs in tone). After reading the sentence, aword changed the color on the screen and then disap-peared. The speakers were orally instructed to utterthe word in a carrier sentence (Reci [kila] navadno,ne posebno. ‘Say [kila] regularly, not in a specialway.’). Each such carrier sentence was repeated.

The recordings took place in several sound-proofrooms (usually radio studios, different locations).Recording was digital, with a standard sampling fre-quency of 44.1 kHz at a 16 bit rate. Recordings werestored on digital storage devices and later transferredto a computer for acoustic analysis. For acousticanalysis, Praat software program [2], was used. Rel-evant words were segmented manually, and then an-alyzed using modified scripts. Normally the first ut-terance of the carrier sentence was analyzed. Du-ration was measured for all stressed and post-tonicvowels, as well as time-normalized f0 and inten-sity contours. For each vowel, 11 points of inten-sity and F0 were measured. Intensity and F0 them-selves were not normalized, as they did not differsignificantly from the absolute values. In this man-ner, 192 words were obtained for analysis, i.e. 96minimal pairs, or 408 vowels. However, 9 words(4.7%) were excluded from the analysis because ofvarious reasons (e.g. incorrect pronunciation, irreg-ular or non-detectable f0).

3. RESULTS3.1. DurationDurations of individual vowels (not whole syllablesnor voiced parts thereof) in the observed words weremeasured, ratios calculated and averaged. The re-sults are presented in Table 1.

The results indicate that the stressed vowel isslightly longer in Class I words, such that differ-ence is independent of any segmental, (sentence) in-tonational and even speaker dependent influences.Moreover, it is consistent across all word types.Also, the difference is never statistically significant(0.1 < p < 0.6). This leads to the conclusion thatno statistically significant differences between bothtonal types could be detected.

3.2. IntensityCross-linguistically, intensity contours are known tocomplement tonal contours. In Slovenian however,no statistically significant differences (p > 0.3) inintonation contours were detected, see Fig. 1. Here,only CVCVCV words are presented, as the results

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Table 1: Duration of vowels with respect to tone.Abbreviations: Dur – averaged sum of individualvowel durations in a word, %v1 – percentage ofthe first vowel with respect to the sum of durationsof all vowels in a word, Ratio II/I – Ratio of aver-age total vowel durations of Class II with respectto Class I words.

Word Class I Ratiotype Dur %v1 %v2 %v3 II/Icv.cv 235 51.3 48.7cvc.cvc 218 61.0 39.0cv.cv.cv 243 35.4 30.0 34.6cvc 122Word Class II Ratiotype Dur %v1 %v2 %v3 II/Icv.cv 220 52.9 47.1 .937cvc.cvc 201 61.8 38.2 .921cv.cv.cv 219 38.6 31.3 30.1 .902cvc 109 .893

for all word types are similar. Previously, inten-sity had not been studied in connection to Slovenian.An interesting discovery is that in words with ante-penultimate stress, a secondary intensity peak in thefinal syllable/vowel is found. This may be indicativeof secondary stress, also connected to tonal promi-nence of final vowels (see Sec. 3.3.).

Figure 1: CVCVCV intensity contours (for eachvowel).

3.3. Fundamental frequencyPrevious studies have already established that Slove-nian tones differ primarily in f0. However, they dis-agree on how this difference is realized and on howit should be interpreted phonologically.

An average CVCV word was realized as pre-sented in Fig. 2. As evident from the graph, stressedsyllables do not differ in f0 (at least not signif-icantly), whereas post-tonic syllables have higherf0 in Class I words, and both contours are falling.Difference in the post-tonic syllable is statisticallyhighly significant (p < 0.005). The situation is

somewhat different in closed syllables, but still sig-nificant (figure not reproduced here).

Figure 2: CVCV f0 contours (for each vowel).

Tones in trisyllables also differ highly signifi-cantly (p < 0.001). The distinction is limited tostressed (antepenultimate) and the final syllables,the former having lower f0 in Class I tone, and thelatter being considerably higher, see Fig. 3. This isa surprising find as acoustic phoneticians have so faronly considered stressed and immediately post-tonicsyllables in Slovenian, not the rest of the prosodicword.

Figure 3: CVCVCV f0 contours (for eachvowel).

Monosyllables differ only marginally signif-icantly (p = 0.042), although a clear tendencyis visible in Fig. 4: Class I has a rising contour,while Class II has a falling one. This seems to bein accordance with the findings in [9, 10, 12]: inthe speech of Central Slovenia, tonal differencesare neutralized in monosyllables. The question,whether this is phonological proper (l.c.), effec-tively neutralizing all tonal contrast in final-stressedwords, positionally phonological or just phonetic,remains beyond the scope of this article. The resultsshould be interpreted with caution: only six tokenswere analyzed for each tone, of which only onewas a monosyllabic word (as monosyllabic minimalpairs are rather rare).

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Figure 4: CVC f0 contours (for the vowel).

4. DISCUSSION AND CONCLUSION

The results of the experiments can be summed upas follows: there is no significant difference in nei-ther duration nor intensity between both tones, whilefundamental frequency is highly distinctive. In di-syllables with initial stress, the post-tonic syllable isusually phonetically distinctive. In trisyllables withinitial stress, it is the final syllable that is the mostdistinctive. Monosyllables also differ in tone. Thestressed and all post-tonic syllables constitute thedomain of the tone. Contemporary Standard Slove-nian, as spoken by educated speakers in Ljubljana,is tonal.

All these findings are connected to the ques-tions (not) addressed in the acoustic investigationsof Slovenian tones in the 20th century. For exam-ple, vowels two or more syllables after the stressedvowel were never taken into account. The presentfindings suggest that it is not the immediately post-tonic syllable, but rather the final syllable, thatis actually phonetically (and phonologically) rele-vant. (Native Slovenian roots do not permit pre-antepentultimate stress, but it can surface in thederivation or inflection.) Now it is also clear, thatSlovenian tones do not simply translate into Highor Low tone (as suggested by [11]) on the stressedvowel, and that all other tonal information is pre-dictable, viz., phonetic. Actual realizations aremuch more complex (Table 2). The acoustic datafrom the antepenultimates cannot be explained byany of the previous phonological descriptions ofSlovenian. Instead, High vs. Low is distributedon the head of the prosodic word (i.e. the stressedvowel) and the right edge of the prosodic word.

Further investigation is needed to account, forexample, for sentence intonation. From a broaderperspective, European tone (or pitch-accent) lan-guages are vastly under-described, and much workis yet to be done. The same is true for the majorityof Slovenian dialects.

Table 2: Prosodic notation, most consistent withthe findings.

Stress Class I Class IIFinal pot ‘sweat’ pot ‘path’Penult "kıla ‘hernia’ "kıla ‘kg’Antepen "Salıtsa ‘joke-dem’ "Salıtsa ‘cup’

5. ACKNOWLEDGMENTSThe author would like to thank Michael Becker,Martin Krämer, Grant Lundberg, Bruce Morén,David Odden, Curt Rice, Dragana Šurkalovic andChristian Uffmann for valuable comments and sug-gestions. Usual disclaimers apply.

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[2] Boersma, P., Weenink, D. 1992−2006. Praat.http://www.praat.org.

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[10] Srebot Rejec, T. 2000. Ali je današnja knjižnaslovenšina še tonematicna. In: Razprave II. razredavolume 17. SAZU 51–66.

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[13] Šuštaršic, R., Tivadar, H. 2005. Perception of tone-micity in Standard Slovene. Govor 22(1), 23–35.

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