In my last post, I wrote about some characteristics of tones (among others, they can “float”) and the theory of their origin – the science of tonogenesis. I mentioned that tones are highly areal: They either have a huge presence in a language family (Niger-Congo & Sino-Tibetan) or hardly show up at all (Indo-European). Even among regions where tones show up in large numbers, there are still significant differences in how they typically behave. Traditionally, tonologists tend to concentrate on either African (esp. Bantu) tone languages or Asian (esp. Chinese) ones, with relatively little conversation between the two camps. This is partly due to historical reason, partly because the points of interests are so very different between these two groups of languages. I will use today’s and my next post to introduce salient characteristics of African and Asian tone languages, and show how their impact on our understanding of phonology and of course, language.

African tones are famous for their mobility. The Bantu language of Chizigula (aka Zigula), spoken in Tanzania and Somalia, provides a particularly striking example. In this language, a verb is either toneless, or one of its syllables carry a H (high) tone. When I talk about verbs, I am really referring to verbal stems, which you can think of the basic form of a verb without all the affixes. As it often happens in African languages, Chizigula has a rich morphological system, with potentially layers of affixes. The interesting thing is, when a Chizigula verbal stem with an H tone gets suffixes, the H tone always moves to the penultimate (second-to-last) syllable in the newly affixed verb. I said “always”, because the H tone is absolutely hellbent on moving, no matter how many syllables it has to jump in doing so. Consider the Chizigula verb for “request”, with and without suffixes, in (1).

(1a)     lómbez                    ‘request’

(1b)    ku-lombéz-a             ‘to request’

(1c)     ku-lombez-éz-a            ‘to request for’

(1d)    ku-lombez-ez-án-a       ‘to request for each other’

Example (1a) shows the verbal stem, /lómbez/, where the H tone is attached to the segment /o/, marked with an accute accent. We take this tonal assignment to be basic and “underlying”, given the verbal stem appears in isolation here. In (1b), with the addition of suffix -a, the H tone moves to the right to the now second-to-last syllable, /be/. In (1c) and (1d), with progressively more suffixes added, the H tone moves further and further to the right (no pun here, for those politically conscious), but true to its form it always ends up with the penultimate syllable, even when this means moving three syllables away from its underlying position.

So Chizigula tone is a travel freak. What’s so interesting about that? Well, as I alluded to in my last post, the consequence of this and other findings about tonal mobility is nothing short of revolutionary for phonological theory. One resultant insight is that tones are “autosegments”: they are autonomous and independent from segments, from which they can leave, across which they can move and onto which they can dock. Phonologists formalise this insight by positing separate tonal tier and segmental tier, linked by association lines. I won’t go deeper into the fine theory, except to say that this formalism, in essence, is what we today know as Autosegmental Phonology. The following graph depicts how the itinerary of Chizigula H tone is represented in this scheme.

Screen Shot 2015-01-19 at 20.04.23
H de-linking and re-association

The H tone is originally linked to the syllable /lom/; under the pressure to have all H tones docked onto the penultimate syllable, the H is delinked from /lom/ and re-links with the penultimate /be/. You can easily extend this scheme to (1c) and (1d): all you have to do is do the same delinking operation, and then re-link the H tone to /ze/ in (1c) and /za/ in (1d).

Another insight gained from Chizigula tones’ unusual migration pattern has to do with the problem of locality. Linguists tend to think that linguistic objects like tones can’t walk around unrestrained from where they should’ve been. In other words, there must be some kind of “locality condition”, by which objects only move to an adjacent position. Chizigula tones moving three syllables away from their underlying position obviously stretches our definition of adjacency. In response to this and other so-called long-distance processes, phonologists now recognise “relativised locality”, in contrast to the stricter version of “absolute locality”. In a nutshell, it’s not the absolute distance (x syllables or y segments) that determines adjacency, but whether there are obstacles along the path of movement. Chizigula tones can do long-distance travel because nothing intervenes on their path; if there were low tones in Chizigula and one of these should stand between H tone and the penultimate syllable, the H tone may well have to cancel its travel plan. One of the languages that do have this blocking effect is Luganda, where H tone spreads freely until encountering an L tone.

(2a) à-, bala, e-, bi-, kópo

(2b) à-bálá é-bí-kópo        ‘he counts cups’

When all the stems and affixes in (2a) stand alone, only the first syllable of /kópo/ has a H tone, and the prefix /à/ has a L tone; the rest are toneless. When these are strung together to form the sentence in (2b), the H tone has spread and occupied four syllables until stopped by the L tone on /à/. This is but one small example illustrating relativised locality – more examples can be found in vowel and consonantal harmony processes.

Thus in just one tonal process, a data point from a language spoken by around 20000 people, we have seen so much of tonal phonology, and tonal phonology at its best. From the way Chizigula H tone moves (and Luganda H tone stops moving), we have a solid piece of evidence showing how our brain manipulates mental objects – the autonomous movement of tones (Autosegmental Phonology) and the condition on their movement (relativised locality). Things will get still better, however, when we move to Chinese tone sandhi next time.

Further reading:

1. Autosegmental Phonology

Goldsmith, John A. 1976. An overview of autosegmental phonology. Linguistic Analysis 2. 23–68

Excellent slides on autosegmental phonology by Jochen Trommer. The figure from this blog is taken from his lide

2. Relativised locality

Nevins, A., & Vaux, B. (2004). The transparency of contrastive segments in Sibe: Evidence for relativized locality. GLOW, Thessaloniki.

Vaux, B. (1999). Does Consonant Harmony Exist. Presented at the Linguistic Society of America Annual Meeting.