Raking test

Trubetzkoy’s theory of distinctive opposition is an aspect of Classical Phonology which discusses the issue of the phoneme and how to identify phonemes in a language. Trubetzkoy (1939) views the phoneme as a linguistic concept or a phonological reality which should be considered purely in terms of its function in the system of a language. Through the theory of distinctive opposition, Trubetzkoy recommends three different kinds of opposition which sounds in human language can enter into. They are:

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(1.) Privative Opposition: This occurs when two phones are identical except that one has a phonetic mark which the other lacks as can be seen in the pairs /f/ ~ /v/, /p/~/b/,

/k^w/~/g^w/, where each pair differs by voicing;

(2.) Equipollent opposition: This is where phonemes differ from others as a result of certain feature each has which others lacks. Examples are /p/~/t/~/k/, /b/~/d/~/g/, /m/~/n/~/ŋ/;

and

(3.) Gradual Opposition: This deals with opposition brought about by the steep nature of the height of the tongue in producing some sounds, usually vowels such as /i/, /e/ and /ӕ/

where there is movemet from high, mid to low.

The theory of distinctive opposition introduces some concepts used for explaining relationships among the phonemes such as the concepts of complementary distribution, free variation and minimal pair test. Complementary distribution is used to differentiate sounds which occur in mutually exclusive environments. Two sounds are in complementary distribution if they never occur in the same context (Bittner, 2013). Sounds of this nature are regarded as allophones of the same phoneme. For example, in English, the sounds [p] and [p^h] are allophones of the phoneme /p/ and they are in complementary distribution – where one occurs, the other does not occur.

Bittner (2013) illustrates this concept with the phoneme /l/. He says that the phoneme is realised as a voiceless allophone [ l ] when it follows /p/, /t/ or /k/ at syllable initial position; when it precedes a vowel, it becomes ‘clear l’; and when it changes to ‘dark l’ it occurs elsewhere before a consonant or a pause. He notes that the three allophones stand for the various realisations of the /l/ phoneme and concludes that since they are members of the same phoneme, they are in complementary distribution.

Free variation (FV) is used for sounds which can be substituted for each other in the same environment without a change in meaning of the lexical item. This is illustrated with the following Igbo examples:

68. a. /l/ and /r/ in mmili or mmiri ‘water’; nli or nri ‘food’

b. /z/ and /r/ in ézì or érì ‘pig’.

Bittner (2013) illustrates the phenomenon of FV with consonantal and vocalic phonemes. He points out that the phoneme /z/ in English word zeal can be realised as a voiceless, or devoiced allophone when whispered, or as a voiced allophone when pronounced ‘normally’. Similarly, he submits that speakers of some non-standard British accents can realise the phoneme /t/ as a glottal stop [ʔ] in English word butter, but when they target at producing a more standard pronounciation, they migth realise it as [t]. The scholar also notes that the phonemes /i:/ and /e/

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at initial positions of the English words economics and evolution, and /i:/ and /aɪ/ at initial position of the English word either is an evidence that vocalic phonemes could be in free variation. Barlow and Gierut (2002) demonstrate sounds in free variation with data from English:

69. [mæp]

[mæp̚]

The scholars point out that though the examples in (69) differ by released [p] and unreleased [p̚], their phonetic difference does not bring about a change in meaning because the two words mean exactly the same thing ‘map’ . With this, they conclude that they do not constitute MP and the sounds [p] and [p̚] are neither contrastive nor function as phonemes in English; but are rather allophones (phonetic variants) of the phoneme /p/.

With MP test, distinctive phones are identified. It is the contrasting phones that constitute phonemes of a language. This is exemplified with data from Igbo:

70. a. oche ‘chair’ b. tàa ‘chew’ c. isè ‘to draw (an object, water, etc)’

ofe ‘soup’ bàa ‘enter, scold’ isò ‘to follow’

The differences in the meanings of the above pairs of words are a result of the differences in their medial, initial and final phonemes respectively, which function to differentiate the meanings of the words.

Barlow and Gierut (2002) illustrate the MP test with data from English:

71 a i. ‘map’ [mæp] ii. ‘map’ [mæp] iii. ‘fashion’ [fæʃən]

‘mat’ [mæt] ‘cap’ [kæp] ‘fasten’ [fæsən]

b i. ‘spy’ [spaɪ] ii. ‘cats’ [kæts]

‘sky’ [skaɪ] ‘caps’ [kæps]

c i. ‘map’ [mæp] ii. cap [kæp]

‘mop’ [mɑp] keep [kip]

The scholars use the examples in 71(a) to show that contrast occurs at different contexts – initial, medial and final positions; for 71 (b), they demonstrate that contrast also takes place on cluster contexts; and finally, the examples in 71(c) are an indication that vowels also contrast. They equally discuss near MPs using cluster-singleton comparisons and vowel versus consonant final comparisons as exemplified below:

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72 a. ‘play’ [plei] b. ‘boat’ [boʊt]

‘pay’ [pei] ‘bow’ [boʊ]

Mbah and Mbah (2010) uphold earlier views on the concept of MP, but further expanded it to cover tone languages. They argue that every word of a language has two tiers: the prosodic and the segmental, and that in determining MP, a perceptible rhythm generated both at the segmental and prosodic tiers whose form is contrasted by a single sound feature apiece must be considered.

In their opinion, when pairs are identical at the autosegmental or prosodic tier, then the contrasting sound will be at the segmental tier and vice versa; and that while the latter is common with tone languages, the former is common with intonational languages (p.161). Mbah and Mbah (2010) differ from Ladefoged (1975) in his contention that in addition to segments of the MP, the words, the unit of analysis, has to rhyme. They argue that it is the actual sounds produced in speech that are used to determine minimal pairs, e.g.

73 (a) key (b) my (c) me (d) lie bee nigh knee why

These examples in (73), to Ladefoged (1975), do not constitute MP because more than one segment sets them apart, but Mbah and Mbah (2010) argue that since the sounds rhyme, they constitute MPs. Mbah and Mbah (2010) also submit that a minimum of pitch variation which results in meaning contrast as well as intonational patterns and tonemes which stretch over syntactic junctures or lexical items respectively but results in meaning contrast form MP, e.g.

74 a. John came.

b. John came?

They also provide evidences from Igbo to buttress their point that words similar at the segmental tier without rhyming at the prosodic tier form MP, e.g.

75 a. akwa ‘cry’ b. oke ‘male’

akwà ‘cloth’ okè ‘boundary àkwa ‘egg’ òke ‘rat’

àkwà ‘bed’ òkè ‘share’

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In the examples in (75), Mbah and Mbah (2010) point out that cry and bed, cloth and egg are tonally equipollent because each segment has a tone which the other lacks. Emenanjo (2015) presents some Igbo data which validate Mbah and Mbah’s (2010) position on MP in tone languages. Some of the data are as follow:

76 a. akwa ‘cry’ b. isi ‘head’ c. igwè ‘iron’

akwà ‘cloth’ isì ‘smell’ ìgwè ‘crowd’

àkwa ‘egg’ ìsì ‘blindness’ igwē ‘sky’

àkwà ‘bed/bridge’

d. ọcha ‘white’ e. oke ‘male’ f. mma ‘beauty’

ọ̀cha ‘whiteness’ okè ‘boundary’ mmà ‘knife’

òke ‘rat’ mmā ‘beauty’

òkè ‘share’

g. idè ‘flood/earthworm’

ìde ‘pillar/basket’

ìdè ‘raffia palm wine’

(Adapted from Emenanjo, 2015:112)

For example 76(d), Emenanjo demonstrates that two apparently identical and even related words can differ in their parts of speech as stated below:

77 a. ọ̀cha ‘whiteness’ (nominal) noun b. ọcha ‘white’ (nominal modifier) adjective

This study adopts the minimal pair (MP) aspect of Trubetzkoy’s theory of distinctive opposition as further developed by Mbah and Mbah (2010) for this study since Igbo is a tone language and relying on it will enable the phonemes of the Ọmambala Igbo to be established.