Yoruba linguistic features

Phonology
The three possible syllable structures of Yoruba are consonant+vowel (CV), vowel alone (V), and syllabic nasal (N). Every syllable bears one of the three tones: high $\langle\rangle$, mid $\langle\rangle$ (generally left unmarked), and low $\langle\rangle$. The sentence (I didn't go) provides examples of the three syllable types:
 * — — I
 * ò — — not (negation)
 * lọ — — to go

Vowels
Standard Yoruba has seven oral and five nasal vowels. There are no diphthongs in Yoruba; sequences of vowels are pronounced as separate syllables. Dialects differ in the number of vowels they have; see above.



The status of a fifth nasal vowel,, is controversial. Although the sound does occur in speech, several authors have argued it to be not phonemically contrastive; often, it is in free variation with .Notably, Ayọ Bamgboṣe (1966:8). Orthographically, nasal vowels are normally represented by an oral vowel symbol followed by $\langlen\rangle$ (i.e., $\langlein\rangle$, $\langleun\rangle$, $\langleẹn\rangle$, $\langleọn\rangle$), except in case of the allophone of  (see below) preceding a nasal vowel, i.e. inú 'inside, belly' is actually pronounced .Abraham in his Dictionary of Modern Yoruba deviates from this custom, explicitly indicating the nasality of the vowel; thus, inú is found under inún, etc.

Consonants
The voiceless plosives and  are slightly aspirated; in some Yoruba varieties,  and  are more dental. The rhotic consonant is realized as a flap, or in some varieties (notably Lagos Yoruba) as the alveolar approximant. Like many other languages of the region, Yoruba has the labial-velar stops and, e.g. pápá  'field', gbogbo  'all'. Notably, it lacks the common voiceless bilabial plosive, which is why is written as $\langlep\rangle$. It also lacks a phoneme ; though the letter $\langlen\rangle$ is used for the sound in the orthography, it strictly speaking refers to an allophone of which immediately precedes a nasal vowel.

There is also a syllabic nasal which forms a syllable nucleus by itself. When it precedes a vowel it is a velar nasal, e.g. n ò lọ 'I didn't go'. In other cases its place of articulation is homorganic with the following consonant, for example ó ń lọ 'he is going', ó ń fò  'he is jumping'.

Tone
Yoruba is a tonal language with three level tones: high, low, and mid (the default tone.Several authors have argued that the mid-tone is not specified underlyingly, but rather is assigned by a default rule (Pulleyblank 1986, Fọlarin 1987, Akinlabi 1985). Evidence includes examples like the following: rí 'see'  aṣọ 'clothing' → ráṣọ 'see clothing', contrasted with rí 'see'   ọ̀bẹ 'knife' → rọ́!bẹ 'see a knife' In the first example, the final vowel of the verb rí is deleted but its high tone easily attaches to the first syllable of aṣọ, the mid tone of which disappears without a trace. In the second example, the Low tone of the first syllable of ọ̀bẹ is not as easily deleted; it causes a downstep (marked by $\langle^{!}\rangle$, i.e., a lowering of subsequent tones. The ease with which the Mid tone gives way is attributed to it not being specified underlyingly. Cf. Bamgboṣe 1966:9 (who calls the downstep effect 'the assimilated low tone').) Every syllable must have at least one tone; a syllable containing a long vowel can have two tones. Contour tones (i.e. rising or falling tone melodies) are usually analysed as separate tones occurring on adjacent tone bearing units (morae) and thus have no phonemic status.Cf. Bamgboṣe 1966:6: The so-called glides […] are treated in this system as separate tones occurring on a sequence of two syllables. Tones are marked by use of the acute accent for high tone ($\langleá\rangle$, $\langleń\rangle$), the grave accent for low tone ($\langleà\rangle$, $\langleǹ\rangle$); Mid is unmarked, except on syllabic nasals where it is indicated using a macron ($\langlea\rangle$, $\langlen̄\rangle$); see below). Examples:
 * H: ó bẹ́ 'he jumped'; síbí 'spoon'
 * M: ó bẹ 'he is forward'; ara 'body'
 * L: ó bẹ̀ 'he asks for pardon'; ọ̀kọ̀ 'spear'.

Effects of Tonality on Computer Coded Yoruba Written Documents
First, the use of the subdots and tone marks otherwise known as diacritic markings are not represented on the conventional keyboards. Therefore, most Yoruba documents are computer coded without the marks. Secondly,Asubiaro, Toluwase V. (2014)Effects of Diacritics on Web Search Engines’ Performance for Retrieval of Yoruba Documents. Journal of Library and Information Studies 12 (1), 1-19 revealed that the use of the diacritics affect the retrieval of Yoruba documents by popular search engines.

Assimilation and elision
When a word precedes another word beginning with a vowel, assimilation or deletion ('elision') of one of the vowels often takes place.See Bamgboṣe 1965a for more details. See also Ward 1952:123–133 ('Chapter XI: Abbreviations and Elisions'). In fact, since syllables in Yoruba normally end in a vowel, and most nouns start with one, this is a very common phenomenon, and indeed only is absent in very slow, unnatural speech. The orthography here follows speech in that word divisions are normally not indicated in words that are contracted as a result of assimilation or elision: ra ẹja → rẹja 'buy fish'. Sometimes however, authors may choose to use an inverted comma to indicate an elided vowel as in ní ilé → n’ílé 'in the house'.

Long vowels within words usually signal that a consonant has been elided word-internally. In such cases, the tone of the elided vowel is retained, e.g. àdìrò → ààrò 'hearth'; koríko → koóko 'grass'; òtító → òótó 'truth'.

Grammar
Yoruba is a highly isolating language.Karlsson, F. Yleinen kielitiede. ("General linguistics") Helsinki: Helsinki University Press, 1998. Its basic constituent order is subject–verb–object (SVO),Rowlands, Evan Colyn. (1969). Teach Yourself Yoruba. English Universities Press: London. as in ó nà Adé 'he beat Adé'. The bare verb stem denotes a completed action (often called perfect); tense and aspect are marked by preverbal particles such as ń 'imperfect/present continuous', ti 'past'. Negation is expressed by a preverbal particle kò. Serial verb constructions are common, as in many other languages of West Africa.

Although Yoruba has no grammatical gender,Ogunbowale, P. O. (1970). The Essentials of the Yoruba Language. University of London Press: London. it does have a distinction between human and non-human nouns; probably a remainder of the noun class system of proto-Niger–Congo, the distinction is only apparent in the fact that the two groups require different interrogative particles: tani for human nouns (‘who?’) and kini for non-human nouns (‘what?’). The associative construction (covering possessive/genitive and related notions) consists of juxtaposing nouns in the order modified-modifier as in inú àpótí {inside box} 'the inside of the box', fìlà Àkàndé 'Akande’s cap' or àpótí aṣọ 'box for clothes' (Bamgboṣe 1966:110, Rowlands 1969:45-6). More than two nouns can be juxtaposed: rélùweè abẹ́ ilẹ̀ (railway under ground) ‘underground railway’, inú àpótí aṣọ 'the inside of the clothes box'. In the rare case where this results in two possible readings, disambiguation is left to the context. Plural nouns are indicated by a plural word.

There are two ‘prepositions’: ní ‘on, at, in’ and sí ‘onto, towards’. The former indicates location and absence of movement, the latter encodes location/direction with movement (Sachnine 1997:19). Position and direction are expressed by these prepositions in combination with spatial relational nouns like orí ‘top’, apá ‘side’, inú ‘inside’, etí ‘edge’, abẹ́ ‘under’, ilẹ̀ ‘down’, etc. Many of these spatial relational terms are historically related to body-part terms.