The functional load of in Hausa

1 Tone in Afroasiatic Contrastive tone is found throughout two branches of Afroasiatic: Chadic and Cushitic. For Chadic, Schuh (2017:91) notes that ‘tone has to be overtly specified for each and every noun’ which ‘shows it to be an important, phonological component of the lexicon’. However, he also notes that exact minimal pairs are uncommon’ (e.g. /L/ vs. /H/ in Margi [mrt], fà‘farm’ vs. fá ‘year’ - Schuh 2017:93). Table 1 shows the low number of nouns distinguished solely by tone.

Lang ISO n = (approx.) Distinguished by tone Bole bol 2000 139 6.95% Bura bwr 600 30 5% Ngizim ngi 1900 76 4% Miya mkf 670 6 0.9% Gude gde 800 4 0.5% Table 1: Low number of tonal minimal pairs in Chadic (interpreted from Schuh 2017:90) Where tone plays a small role in distinguishing morphemes, tone is said to have a low functional load, claimed for Chadic languages Makary Kotoko [mpi] (Allison 2012:38) and Goemai [ank] (Tabain & Hellwig 2015:91), and for Cushitic as a whole (Mous 2009), e.g. Awngi [awn] (Joswig 2010:23-24). However, most statements do not provide clear statistics to support their position. 2 Quantifying the functional load of tone In this talk, we present the first study quantifying the functional load (FL) of tone in Hausa. While there is a long history measuring FL in (Martinet 1955, 1977; Hockett 1967; Wedel et al. 2013a,b; Oh et al. 2013, 2015), very few studies have looked at tone. Our study employs a methodology measuring entropy (H), an information theoretic term meaning the amount of unpredictability in a system. From a digitized Hausa lexicon of 10,768 lexemes, we assess the FL of four phonological properties: (1) consonant quality, (2) quality, (3) tone, and (4) vowel length. We do this by quantifying a baseline entropy for the lexicon (HB), then assess the change in entropy if we hypothetically merge phonological contrasts (e.g. merging consonant quality: dala, tala, mana > XaXa). The FL is the amount of uncertainty (=entropy) that is lost by the merger (Hall et al. 2016). Doing this for all contrast mergers, and calculating it for all lexemes, vs. for nouns, verbs, and graded verbs, results in a set of FL measurements for the lexicon, shown below. One can see that while the FL for consonants is high (FLC = .103), it is low for (FLV = .013), and half that value for tones (.006).

Unique entries Types of hypothetical mergers testing FL before merger No C Qual No V Qual No Tone No Vowel Length (VL) 10489 4026 9264 9932 10268 All HNoC = 11.975 HNoV = 13.177 HNoT = 13.278 HNoVL = 13.326 (n=10768) HB = 13.357 FLC = .103 FLV =.013 FLT =.006 FLVL =.002 6665 3142 6225 6536 6620 noun HNoC = 11.617 HNoV = 12.604 HNoT = 12.674 HNoVL = 12.693 (n=6776) HB = 12.702 FLC = .085 FLV =.008 FLT =.002 FLVL =.001 2417 506 2081 2274 2350 verb HNoC = 8.983 HNoV = 11.023 HNoT = 11.151 HNoVL = 11.198 (n=2452) HB = 11.239 FLC = .201 FLV =.019 FLT =.008 FLVL =.004 2419 529 2297 2419 2385 verb grade HNoC = 9.047 HNoV = 11.166 HNoT = 11.240 HNoVL = 11.220 (n=2452) HB = 11.240 FLC = .195 FLV =.007 FLT =0 FLVL =.002 Table 2: Assessing the functional load of tone in Hausa 3 Discussion In contrast to Hausa, previous research in tonal languages Mandarin and has shown that while the FL of consonants is similarly much higher compared to vowels, the FL of vowels is largely equivalent to the FL of tone, showing their equal lexical importance (Surendran & Niyogi 2003, 2006; Surendran & Levow 2004; Oh et al. 2013, 2015). We put forward the Functional Load of Tone (FLT) hypothesis, which states that in languages where the functional load of lexical tone is low (e.g. Hausa), the use of grammatical tone is relatively high, and vice versa. This hypothesis is supported by the large role grammatical tone plays in Afroasiatic tone systems (Mous 2009, Schuh 2017), and its diminished role in these Chinese languages. 4 References Allison, Sean. 2012. Aspects of a grammar of Makary Kotoko (Chadic, Cameroon). Dissertation, University of Colorado. Hall, Kathleen Currie, Blake Allen, Michael Fry, Scott Mackie, and Michael McAuliffe. 2016. Phonological CorpusTools, Version 1.2. [Computer program]. Available from PCT GitHub page. Hockett, C. 1967. The quantification of functional load. Word 23:320–339. Joswig, Andreas. 2010. The phonology of Awngi. SIL International. Martinet, A. 1955. Économie des changements phonétiques. Traité de phonologie diachronique. Francke: Berne. Martinet, A. 1977. Some basic principles of functional . La Linguistique 13(1):7-14. Mous, Maarten. 2009. The typology of tone in Cushitic. WOCAL 6, Cologne, 16-21 August 2009 Oh, Yoon Mi, Pellegrino, F., Coupé, C., & Marsico, E. 2013. Cross-language comparison of functional load for vowels, consonants, and tones. Proceedings of interspeech 2013, Lyon, France. 3032–3036. Oh, Yoon Mi, Christophe Coupé, Egidio Marsico, François Pellegrino. 2015. Bridging phonological system and lexicon: Insights from a corpus study of functional load. Journal of Phonetics 53: 153- 176. Schuh, Russell. 2017. A Chadic Cornucopia. Oakland: eScholarship. Surendran, Dinoj, & Gina-Anne Levow. 2004. The functional load of tone in Mandarin is as high as that of vowels. Speech Prosody 2004, International Conference. Surendran, Dinoj & Partha Niyogi. 2003. Measuring the usefulness (functional load) of phonological contrasts. Technical report TR-2003–2012. Department of Computer Science, University of Chicago. Surendran, Dinoj & Partha Niyogi. 2006. Quantifying the functional load of phonemic oppositions, distinctive features, and suprasegmentals. In Ole Nedergaard Thomsen (ed.), Competing models of language change. Amsterdam/Philadelphia: John Benjamins. Tabain, Marija & Birgit Hellwig. 2015. Goemai. JIPA 45:88-104. Wedel A, Jackson S., & Kaplan A. 2013. Functional Load and the Lexicon: Evidence that Syntactic Category and Frequency Relationships in Minimal Lemma Pairs Predict the Loss of contrasts in Language Change. Language and speech 56(3):395-417. Wedel A, Kaplan A, & Jackson S. 2013. High functional load inhibits phonological contrast loss: a corpus study. Cognition 128(2):179-186.