CC BY-ND
18
National Research University Higher School of Economics Journal of Language & Education Volume 3, Issue 2, 2017
Jelili Adewale, A. (2017). More on the Categorial Status of (T)abi in Yoruba Grammar. Journal of Language and Education, 3(2), 6-13. doi:10.17323/2411-7390-2017-3-2-6-13
More on the Categorial Status of (T)abi in Yoruba Grammar
Jelili Adewale Adeoye
Ekiti State University
Correspondence concerning this article should be addressed to Jelili Adewale Adeoye, Department of Linguistics and Nigerian Languages, Faculty of Arts, Ekiti State University, Iworoko road, Ado Ekiti, Ekiti State, Nigeria, 360213. E-mail: adeoyejelly@gmail.com
Yoruba language is one of the major languages spoken in Nigeria. The term is also used to refer to the language and the native speakers. As shown in Oyetade, Yoruba language is spoken in six states that constitute the southwest of Nigeria - Lagos, Oyo, Osun, Ogun, Ondo, and Ekiti. This study investigated the Standard Yoruba used in the Southwest Nigeria by focusing on the conjunction t(abi). Findings reveal that there are varieties of Yoruba language based on the location of the speakers and the state they occupy in Nigeria: Oyo dialect, Egba dialect, Ekiti dialect, Ondo dialect and Owo dialect to mention a few. Previous scholarly works on Yoruba grammar show that (t)abi performs two functions and it is ascribed with two nomenclatures namely conjunction and polar question word. However, this present paper provides another view that is different from the views of the earlier scholars. Findings in this study reveal that t(abi) is a conjunction in all its positions of occurrence and the researcher argues against its use as a polar question word. It is established in this study among other things that its occurrence at sentence initial position is as a result of ellipsis. The study also maintains that where it appears at sentence medial position, the polar question word has been deleted.
Keywords: Yorubá, conjunction, polar question word, T(àbi)
Conjunction and question words are integral parts of the universal grammar and every language has the two in its repertoire (lexicon). No language has been reported where the two are absolutely missing. Conjunction is a grammatical category that joins words, phrases, clauses and sentences together while polar question words in Yoruba are interrogative particles that are adjoined to a declarative sentence to make it interrogative. The grammatical category (conjunction) and the interrogative particle (polar question) are used to show different syntactic structures.
However, over the years, Yoruba grammarians like Bamgbose (1967, 1990), Awobuluyi (1978), Ilori (2010) and Ajiboye (2013) have continued to ascribe two functions to (t)abi from the traditional linguistic approach. None of these scholars, to the best of our knowledge, has queried the assertion that (t)abi is a conjunction and a polar question word. It shall be argued in this paper that all occurrences of (t)abi perform the function of a conjunction. It will also be shown that there is no single word that can combine the functions of a polar question and a conjunction. For instance, a polar question word serves as the introducer of interrogative sentence while a conjunction occurs between nouns, clauses and sentences. This significant
difference is an indication that (t)abi cannot perform the two functions simultaneously.
This paper is divided into four sections. Section one will form the introduction. In section two, the researcher discusses the previous analysis of (t)abi as a conjunction and a polar question word. In section three, arguments will be presented to support the present proposal. Section four is the conclusion.
Materials and Methods
Previous Analysis of (T)abi
Previous analysis of (t)abi falls into two categories: treating it as a conjunction in one context and a polar question word in another context (Bamgbose 1967, 1990; Awobuluyi, 1978; Ilori, 2010; Ajiboye, 2013).
Bamgbose (1967) groups (t)abi "or", sugbon "but"
yala.....tabi "whether.....or" as conjunction as shown
in the examples below:
1 a. E o gberin (t)abi e o ni Will you join in the song or gberin? won't you?
b. Se ki a ja.de (t)abi ki a Shall we go out or stay? duro?
A keen look at the examples given above will show
This article is published under the Creative Commons Attribution 4.0 International License.
that 1 (a & b) are interrogative sentences. In 1 (b) (t)abi functions as a conjunction because the polar question word Se "did"(polar question word) is adjoined to the sentence while in 1 (a) (t)abi functions as the polar question word. Since example 1(b) is grammatical in Yoruba, one may argue that the polar question word in
1 (a) has been deleted. Moreover, Bamgbose (1990, p. 190) asserts that (t)abi functions as both a conjunction and an interrogative particle. He opines further that when two opposite sentences are joined together by (t) abi or when it appears at the sentence initial position, such a sentence will give interrogative connotation. See the examples below:
2 a. E le duro de wa (t)abi ki You can wait for us or go home.
e maa lo sile.
b. Se e ti se tan (t)abi e si Are you through for the day or fee sise si i? you still
c. Yala e wa (t)abi e o wa, Whether you come or you a a se e. don't, we will do it.
d. O ti lo(t)abi ko i ti i lo? Has he gone or he hasn't?
e. O tan (t)abi o ku? Has it finished or it remains?
f. Abi e fee ba wa lo? Are you willing to follow us?
(Bamgbose, 1990, p. 190)
In 2 above, Bamgbose (1990) asserts that the function of (t)abi is dependent on the syntactic environment. It is a conjunction in 2 (a, b & c) while the same word is a polar question word in 2 (d, e & f). However, contrary to Bamgbose's view, consider the examples below:
3 a. Se o ti tan (t)abi se o ku? Has it finished or it remains?
b. Nje o ti lo(t)abi nje ko i Has he gone or he hasn't? ti i lo?
If (t)abi is a polar question word as asserted by Bamgbose (1990) in 2 (d, e & f) what is the function in
3 (a & b)? In addition, a closer look at 2 (f) will show that a clause has been deleted prior to (t)abi occurrence at the initial position (see Bamgbose, 1990). Moreover, contrary to Bamgbose's (1967; 1990), Awobuluyi (1978, p. 106) classifies (t)abi as a disjunction and he notes that the word is used within nouns, adverbs and sentences. See the examples below:
4 a. Igba wo ni ki n wa, ni When should I come in the
aaro ni (t)abi ni ale? morning or in the evening?
b. O ti de (t)abi ko i ti i de? Has he come back or he hasn't?
c. Abi ko nii wa ni? Or is it that he doesn't plan to
come?
(Awobuluyi, 1978, p. 106).
In the examples in 4 above, it is shown that nigbawo "when" is the question word in 4 (a) and (t)abi is the conjunction in the sentence; while the same (t)abi is the question word in 4 (b&c). A closer look at example 4 (a) will show that (t)abi is a conjunction in both 4 (b&c) because a question word can be added to 4 (b)
while the clause before (t)abi in 4 (c) has been deleted. Furthermore, the question word in 4 (c) has been deleted. See these examples:
4 d. Abi se ko nii wa ni?
Or is it that he doesn't plan to come?
4 e. Abi se ko gbo ni? Or is it that he doesn't
comprehend?
Awobuluyi (1978) also named (t)abi a disjunction, that is, a separate entity from conjunctions. However, it must be noted that disjunction or adverse conjunction is an integral part of the coordinating conjunction, thus the appropriate nomenclature for (t)abi is disjunctive conjunction or adverse conjunction.
Ilori (2010) identifies ati/ti and, (t)abi "or" as nominal conjunction in Yoruba. See the example below:
5 a. Mo n fe [moto (t)abi ile]
1sg prog. Want vehicle or house I want a car or house.
He also notes that (t)abi "or" is used as a clausal conjunction in interrogative expressions. See the examples below:
5 b. Mo ri i (t)abi mi o ri i?
1sg see it or 1sg neg see it Did I not see it? c. Won ti jewo(t)abi won o ti i jewo?
3pl pert confess or 3pl neg pert neg confess Have they confessed or not?
The researcher agrees with Ilori's claim in 5 (b & c) that (t)abi is a clausal conjunction in interrogative construction but Ilori (2010) has not provided the question words in the sentences. He (Ilori) has not been able to explain the function of (t)abi when it occupies a sentence initial position. This present study shows that examples 5 (b and c) can be rendered in these forms and it will be grammatical. See the examples below:
6 a. Se mo ri i (t)abi se mi o ri i?
Ow 1sg see it or Ow 1sg neg see it Did I not see it or not?
b. Nje won ti jewo (t)abi nje won o ti i jewo?
Ow 3pl pert confess or Ow 3pl neg pert neg confess Have they confessed or not?
If the sentences in 6 (a and b) are grammatical in Yoruba, the researcher suspected that the question words in 5 (b and c) have been deleted. Moreover, it is worth noting that (t)abi joins sentences of equal status where one is assertive the other is negative. It is also observed that when the first clause is introduced by polar question words such as se and nje, the question word is always deleted in the second clause in Yoruba utterances (see example 1 b and 2 b above), this, the researcher assumes must have made some scholars
think that (t)abi is the question word in the second sentence. However, if examples 6 (a and b) are grammatical; thus, the polar question in the second clause has undergone ellipses.
Ajiboye (2013, p. 10) makes two assertions with respect to (t)abi. First, he claims that there are three lexical items having the same segmental and tonal features in the form of (t)abi but function differently; one function as a conjunction, the second as Yes-no interrogative particle and the third as a kind of Wh-word. Secondly, he notes further that the kind of interrogative particle that comes up depends on the syntactic context and the type of structure. Lastly, he assumes that (t)abi is one and the same lexical item that demonstrates ambiguity between those possible meanings, and one can only appeal to context in order to determine which meaning is intended. See the examples below:
7 a. Yaradua de,(t)abi? Did Yaradua arrive?
b. (T)abi musulumi? Is it a muslim?
c. Ninu ki Ade lo oko (t) Is either Ade goes to the farm abi ki o lo oja. or the market.
d. Ade lo oko (t)abi o sun? Is it the case that Ade went to
farm or he is asleep?
(Ajiboye, 2013, p. 10)
Contrary to the assertions in Ajiboye (2013, p. 10) above, (t)abi is one lexical item in all its position of occurrence and its syntactic position does not determine its function and it does not demonstrate ambiguity of any kind which can be determined by context. See the examples below:
8 a. Se Yaradua de (t)abi Se Has Yaradua arrived or not?
Yaradua ko de?
b. Nje musulumi ni (t)abi nje Is he a Muslim or not? musulumi ko?
c. Sebi Ade lo si oko (t)abi o Is it a fact that Ade went to sun? the farm or he slept?
In reaction to Ajiboye's assertion that (t)abi is a polar question in one context, a content question in another and a conjunction in some other environment, a closer look at the examples in 8 (a, b & c) above, will show that (t)abi has a peculiar function which is a clausal conjunction. In addition, a content question in Yoruba has a strong [Wh-feature] that forbids any other word to replace it. Moreover, when polar question words are adjoined to where (t)abi is purported to be a polar question word like the examples in 8 above what happens to (t)abi? As the researcher has noted earlier, (t)abi combines two sentences with equal structure (S1 conj S2), what happens in most cases is the deletion of the question word (Qw) and NP of S2 to avoid repetition. Observe that 8 c is deviant when the question word (Qw) is attached to S2; we suspend the
explanation for this to the next section.
Results and Discussion
The Status of (T)abi Re-Visited
In the reviewed works above, scholars have claimed that (t)abi functions as both a polar question and a conjunction. However, based on the earlier assertion that (t)abi is a conjunction in all ramifications, the researcher presents the following arguments:
i. Why is it that only (t)abi functions as both a conjunction and a polar question whereas, no other conjunction can perform the same function and no other polar question word can act as a conjunction as well?
ii. That polar question words are adjoined to a declarative sentence to form an interrogative sentence. The question is: how do we account for the instances where (t)abi appears at the sentence initial position?
iii. When (t)abi co-occur with other polar question words, what specific function does it perform? If it is a conjunction, can it be a polar question as well?
iv. Finally, why is it that it is only (t)abi that can occur at the initial, medial and final position as a polar interrogative sentence while other polar question words are either restricted to the sentence initial, medial or final position?
Based on the observations above, we present the following claims to support our arguments.
However, Polar question formation in Yoruba involves the process of adjoining the polar question words to the existing declarative sentences. See the examples below:
9 a. Ade lo si oko Declarative NP go to farm Ade went to the farm.
b. Se Ade lo si oko? Qw NP go to farm Did Ade go to farm?
c. Sebi Ade lo si oko? Qw NP go to farm Ade went to the farm, didn't he?
d. Nje Ade lo si oko? Qw NP go to farm Did Ade go to the farm?
e. Ade ha lo si oko bi? NP Qw go to farm Qw Did Ade go to the farm?
In the examples 9 (a-e), it is discovered that the polar question words are adjoined to the declarative sentence to form polar interrogative sentences. However, in examples (2 f and 7 b) if it is assumed that (t)abi is adjoined to the declarative sentence as it appears at sentence initial position to produce the outcome like the ones in 9 above, let us consider instances where (t)abi is sandwiched between two
sentences. See the examples below:
10 a. Ade lo (t)abi ko lo?
NP go Ow neg. go
Did Ade go or he didn't?
b. Olu duro (t)abi o jokoo?
NP stand Ow he sit
Olu stood or he sat down?
A closer look at example 10 (a-b), will reveal that (t)abi in these sentences is neither inserted nor adjoined. Bamgbose (1990, p. 190) observes among other things with respect to example (2 f and 7 b) and (10) that when two opposite sentences are combined with (t)abi or where (t)abi appears at a sentence initial position, it normally has interrogative connotation. He notes further that when (t)abi occupies a sentence initial position, the clause before it has been deleted. However, this assertion in Bamgbose (1990) is an indication that (t)abi is not adjoined to a declarative sentence in example (2 f and 7 b). Based on this, (t) abi has violated the one of the rules of polar question formation in Yoruba. Secondly, where it occurs between two opposite sentences, a polar question word can be added to such sentences. See the examples below:
11 a. Se Ade lo (t)abi se Ade ko lo ni?
Ow NP go conj. Ow NP neg. go foc.
Did Ade go or not?
b.* Sebi Ade lo (t)abi sebi Ade ko lo ni?
Ow NP go conj. Ow NP neg. go foc.
Ade went or he did not?
c. Nje Ade lo (t)abi nje Ade ko lo ni?
Ow NP go conj. Ow NP neg. go foc.
Did Ade go or he didn't?
In examples 11 (a-c), it is discovered that (t)abi performs conjunction function as opposed to polar question as shown in 10 (a & b). These examples in 11 (a-c) point to the fact that the polar question words in 10 (a & b) have been deleted. Moreover, Se, sebi, nje in (11 a-c) of the clause (S1) controls the structure in (S2). However, 11 b seems deviant; Adeoye (2015) argues that sebi is derived from se # abi that is why the contiguous co-occurrence of sebi and abi may not yield a grammatical sentence in Yoruba. This assertion may look plausible but in Yoruba a low tone cannot displace a high tone as shown in the concatenation. Moreover, this study still maintains that in the distant past in the historical development of Yoruba se # abi must have fused together to produce a polar question word because in some Yoruba dialects the word is sebi; this is an indication that the merger of the high and low tone has produced a mid tone which is a plausible tonal process. This process is attested in Moba dialect (see Abiodun & Ajiboye, 2008). It must be noted
however, that sebi and sebi are in free variation in the Yoruba language, that is, they have same semantic content. Another test to show that t(abi) is not a polar question word is that no other polar question word such as se, sebi and nje have the same distribution as t(abi), that is, they must be able to conjoin two independent sentences. See these examples:
12 a.* Ade lo .se ko lo NP go Ow neg. go Ade went did not go
b.* Ade lo sebi ko lo NP go Ow neg. go Ade went didn't not go
c.* Ade lo nje ' ko lo NP go Ow neg. go Ade went did not go.
d. Ade lo t(abi) ko lo NP go conj. neg. go Ade went or he didn't
While examples in 12 (a-c) are ungrammatical, example 12 (d) is grammatical. This is a clear indication that (t)abi is a conjunction. And, no real polar question word can combine two opposite sentences. Moreover, no other conjunction has been reported in Yoruba to perform polar question word functions. If this is the case, why is (t)abi an exception? However, with respect to the arguments above, three hypotheses are proposed by the researcher to account for (t)abi in Yoruba.
Hypothesis (1) (t)abi is a polar question word and a conjunction.
Hypothesis (2) (t)abi is a polar question word.
Hypothesis (3) (t)abi is a conjunction (disjunctive).
To start with the first hypothesis, the researcher proposes a Complementizer Phrase (CP) Structure for a polar question interrogative sentence where the polar question word occupies the C, CP position and it takes IP as its complement. Moreover, the study also proposes a ConjP that is dominated by IP x and it combines two sentences (IP n and IP m) together. The proposed structures are represented below:
13 a.
CP
IP
Ow
C
b.
IP X
IP n
ConjP
IP m
These structures in 13 (a-b) will be used for the analysis of hypothesis (1) in example 13 below:
14 a. Olu lo. Olu went. Declarative
b. (T)àbi Olu lo . / ? Did Olu go? Or Olu went.
c. Olu lo t(àbi) ko Did Olu go or Olu went or he
lo. / ?
not?
didn't.
d. Se/Nje/Sebi Olu Did Olu go or lo (t)abi ko lo? he didn't
The examples above are presented on tree diagrams for clarification
15 a.
IP
DP
Olu
15 b. i CP
VP
lo
Spec
15 b. ii
T(àbi)
ConjP
Olu lo?
Conj'
Conj
T(àbi)
IP
Olu lo
15 c. i
15 c. ii
IP
DP
Olu
DP
Olu
lo
CP
V Spec C'
IP
t(àbi) ko lo?
IP
VP
ConjP
V
Conj'
Conj IP
lo
t(àbi)
ko lo.
C
15 d. i
Spec C
C
IP
Se DP I'
Ade I VP
CP
V Spec C
lo
IP
t(abi)
ko lo?
15 d. ii
Spec C
C
Se DP I'
Ade I VP
ConjP
Conj.
lo
Conj
t(abi)
IP
ko lo.
Based on our assertion in hypothesis (1), examples 14 (b, c and d) will have two reading as shown in 15 (b, c and d) diagrammatically above. However, example 15 d (i) shows that there are two sentences, Se questions the first sentence, while (t)abi questions the second sentence whereas example 15 d (ii), depicts that there are two sentences; the first sentence is questioned by Se while (t)abi combines the second sentence to polar interrogative sentence (first sentence).
The conclusion that will be drawn from the tree diagrams above is that the assertion in hypothesis (1) is ambiguous, because where (t)abi is sandwiched between two sentences, it would either function as a polar question word or a conjunction. Moreover, when a polar question word is adjoined to the same sentence the function of (t)abi will also remain the same. It must be noted that Yoruba permits the co-occurrences of two polar question words in a sentence and these do not result in change of their functions. See these examples:
16 a. Se Ade lo bi?
Ow NP go Ow Did Ade go?
b. Nje Ade lo bi? Ow NP go Ow Did Ade go?
c. Se Ade ha lo bi? Ow NP Ow go Ow Did Ade go?
The examples in (16) above show that the occurrence of two or more polar question words in a sentence do not change the function of one of the two as opposed to example 15 d (ii) above. Moreover, it is pertinent to note that where (t)abi co-occur with other conjunctions like yala/boya its function remains as a conjunction. See the examples below:
17 a.
b.
Yala ojo ro (t)abi ko ro maa gbin igbado. Conj. NP rain Conj. Neg rain fut. plant maize Whether it rains or not I will plant maize
Boya O lo (t)abi ko lo mi o mo. Conj. Pro go conj. Neg go Pro Neg know Whether he went or not I don't know In addition, if t(abi) is placed as a question word and a conjunction on the same node on a tree diagram, the structure will be cumbersome for analysis and it will generate a grammar that is hard to comprehend.
Since, Hypothesis (1) cannot provide a unified approach for the analysis of (t)abi, it is pertinent to make recourse to hypothesis (2). In hypothesis (2), it is stated that (t)abi is a polar question word in all its position of occurrence thus a CP structure is proposed where C projects into CP and it takes IP as its complement. The structures in 15 b (i) 15 c (i) and 15 d (i) will be applicable, but example 17 (a and b) will pose a problem to this assertion in hypothesis (2). See the tree diagram in 18 below:
C
V
IP
ConjP
Conj' Conj. ip
VP
Yalà DP
Öjo I
VP
ConjP Conj
ro Conj IP
■ I Д
tàbi ko ro
v
gbin
DP
àgbàdo
Olu
VP
V'
V
b Olu lo (t)abi ko lo. Olu went or he didn't. IP2
DP
I'
VP
Olu
ConjP Spec Conj'
Conj
(t)àbi
DP
The structure in 18 above and other examples where t(abi) functions as a conjunction will show clearly that hypothesis (2) is not plausible. Thus, it is imperative to look for a unified analysis to capture tfabi) in all its position of occurrence in Yoruba sentences. However, hypothesis (3) may offer a plausible explanation for the occurrences of t(abi).
Hypothesis (3) asserts that all occurrences of (t)abi is a conjunction. In line with this assertion, a ConjP-Structure is proposed, where (t)abi occupies Conj that projects into ConjP and it takes IP or CP as its complement. Moreover, the ConjP can occur between IP n and IP m (declarative sentences). See the tree diagrams below:
19 a. T(abi) Olu lo. Or Olu went.
ConjP
I
Neg. kö
VP
lo.
d. Se / Nje / Sebi Olu lo(t)abi se,nje ko lo? Did Olu go or he didn't?
CP2
Spec
Conj
t(àbi)
CPi
Sé ko lo?
lo.
V
0
V
The assertion put forward in hypothesis (3) looks more plausible and it provides a uniform approach to the status of (t)abi in all its places of occurrence. Based on this fact, it is argued that whenever (t)abi occupies a sentence initial position, the clause or sentence before it has been deleted (see Bamgbose, 1990). It is also submitted that when it appears between two sentences, the polar question word has been deleted at the base. Thus, its (polar question word) presence becomes optional. The researcher also upholds the popular belief of Yomba grammarians like Awobuluyi (1978) and Bamgbose (1990) on the use of voice raising to produce a polar question because of its cross linguistic evidence. This study asserts that voice raising to produce a polar question must have been responsible for the claim that t(abi) is a polar question word by some Yoruba scholars. It is also posited that there is no specific way to differentiate sentences with a raised voice and the sentences without a raised voice when they are reduced to writing. However, the researcher opines that Yes / No questions in Yoruba can be interpreted just like the ^-features of N items based on its syntactic position (see Ilori, 2010). Thus, it has a weak [WH] feature that is why it can be deleted in some syntactic environment; and its presence may be optional in other environment. Finally, this paper submits that t(abi) is a conjunction in all its place occurrence in sentences.
Conclusion
This paper provides another argument that is quite different from the views of the earlier scholars. This paper challenges the traditional approach of the use of (t)abi which ascribes two nomenclatures (lexical category - conjunction and functional category - polar question word) and use for it. The study establishes that the occurrences of t(abi) in all syntactic environments is a case of a conjunction. The paper also asserts that where it appears at a sentence initial position, the question word in the sentence has been deleted. It is also established that when it is sandwiched between two sentences the question word has been deleted or its presence becomes optional. Moreover, this study submits that when it combines two sentences where the first clause is introduced by a polar question word, the same polar question word controls the second sentence but in utterances it is always deleted. However, this paper supports the claim that raising of the voice can be used to produce a polar question in Yoruba and in such an utterance the polar question is always deleted. This research is limited to lexical categorization of t(abi). Moreover,
the deviance in the co-occurrence of sebi and abi in an interrogative sentence needs further research, maybe an incursion into Yoruba dialects may provide a clear answer. Furthermore, Yoruba lexical categories need a total reappraisal. In English language for instance, a definite number of lexical categories are taught in any grammar course. However, Yoruba grammar which has been undergoing research for decades has not evolved any definite number of word classes. This is a challenge that scholars cannot afford to run away from.
References
Abiodun, M. A., Ajiboye, J. O. (2008). High - low (HL) tone simplification in Moba dialect of Yoruba. A Journal of African Studies, 5(3), 148-156. Ajiboye, J. O. (2013). A comparative study of Yes - No question in Awori, Igbomina, Ikale, Moba, and Owe dialects of Yoruba. In F. A. Fabunmi & A. S. Salawu (Eds.), Readings in African Dialectology and Applied Linguistics (pp. 3-24). München, Germany: Lincom. Awobuluyi, O. (1978). Essentials of Yoruba grammar.
Ibadan, Nigeria: Oxford University Press. Bamgbose, A. (1967). A short Yoruba grammar. Ibadan,
Nigeria: Oxford University Press. Bamgbose, A. (1990). Fonoloji ati girama Yoruba [Phonology and grammar of Yoruba]. Ibadan, Nigeria: University Press. Chomsky, N. (1981). Lectures on government and
binding. Dordrecht, Netherlands: Foris. Chomsky, N. (1986). Barriers. Cambridge, MA: MIT Press.
Chomsky, N. (1995). A minimalist program. Cambridge,
MA: MIT Press. Dada, S. A. (2015). Aspects of compounding in Yoruba.
Journal of West African Languages, 42(2), 43-54. Ilori, J. F. (2004, August). The categorial status of 'oun': A Yoruba perfective conjunction. Paper presented at WALC, University of Ibadan, Nigeria. Ilori, J. F. (2010). Nominalc constructions in Igala and Yoruba (Unpublished doctoral dissertation). Adekunle Ajasin University, Akungba Akoko, Nigeria.
Oyetade, S. O. (2007). Language endangerment in Nigeria: Perspective on Akoko languages of southwest. International Journal of the Sociology of Language, 184, 169-184. Yusuf, O. (1997). Transformational generative grammar: An introduction. Ijebu-Ode, Nigeria: Shebiotimo Press.
Yusuf, O. (1998). Fundamentals of syntax and the study of Nigerian languages. Ijebu-Ode, Nigeria: Shebiotimo Press.
