Vowels in harmony - Kera

Kera is a Chadic language, spoken in Chad. Kera has 6 vowels, which we will call i, e, a, o, u and ǝ. (ǝ is a bit like the second vowel ‘er’ in ‘butter’)

Each of these vowels has qualities called ‘features’ as you can see in this table. A plus sign before the feature means the vowel includes this feature. A minus sign means “not this feature”.







+high i ǝ u
-high e a o

(In linguistics, front is usually called –back, but we won’t worry about that here.)

‘High’ means that the middle of the tongue is high in the mouth. Try saying   i, ǝ, u   followed by e, a, o and see if you tongue drops a bit – in fact your jaw will drop a bit.

‘Front’ means towards the front of the mouth. Try saying i, e and comparing them with u, o. You may notice that for u and o, your lips come forwards – this actually helps your tongue to be further back relative to the front of your mouth.

‘Round’ means that your lips are in a round shape. Try the last comparison again – not only did your lips come forward, but they also became rounded. This is very clear when you alternate between u and i. But also between e and o.

Kera has vowel harmony. This means that there are rules about which vowels can appear together in a word. Sometimes words are not allowed to have both the positive and negative version of a feature. E.g. if high and – high cannot be together in a word then the word cannot have both i and o.

Before I tell you the Kera words, here are a few things you need to know.

Suffixes are additions after the word that change the meaning. In Kera, they are often a single sound, and if too many consonants come together because of suffixes, a vowel will be added. Kera does not allow 3 consonants together. This extra vowel is called an epenthetic vowel.


And a little bit of Kera to get you started…

Verbs:                         mirk… means ‘greet’

                                 baad… means ‘wash’

                                 ǝsk…. means ‘hear’

                                 vǝǝg….means ‘make empty’

Nouns:                         cǝǝr…means ‘head’


-n ‘action finished’

-n ‘me’   (The placing of the suffix makes it clear which one it is)

-t ‘repeatedly’

-u ‘him/his’

-a ‘her’

-i  ‘your/you (f)’

-e  ‘imperfective’ (action not yet complete)


For each of the lines beginning with Q, can you fill in the correct vowel in each slot? (Answers below)



1. For epenthetic vowels in verbs, if there isn’t a vowel in the suffix, just copy the first vowel.

Q       mirk___t___n    ‘greets me repeatedly’


2. If there is a suffix vowel, copy that.

Q    mirk__tu    ‘greets him repeatedly’

Q    mirk__tnu   ‘greeted him repeatedly’


3. If one vowel is high, the other vowels also become high (moving directly upwards in the table).

Q   mirka   becomes    m___rk__   ‘greet her’

Q  baadu   becomes    b___d____  ‘wash him’


4. Vowels that are not front or round, but which are high, become a front vowel providing the suffix is a high front vowel, and become a round vowel if the suffix is a high round vowel.

Note: If any of the vowels are not originally high, this doesn’t work.

Don’t forget to apply rule 3 if it is relevant, but also notice what the vowel was originally!

Q   cǝǝri   >    c __r__     ‘your head’

Q  cǝǝru  >    c___r___   ‘his head’

Q  ǝski  >     __sk___   ‘hear you’

Q  ǝsku  >   ___sk____  ‘hear him’

Q   ǝske   >  ___sk___   ‘hear’

Q  vǝǝge   >   v___g____  ‘is emptying’

Q   baadi   >   b___d___   ‘wash you’


5. In nouns, all vowels are the same except the last vowel if it ends the word. That last vowel can be anything.

Q. Which of these words could be real Kera nouns?

dǝbǝǝbǝr          ‘lizard’

kaasow            ‘millet’

kefter              ‘book’

kupurki            ‘male goat’

gadaamo          ‘horse’

cǝcerkǝ            ‘vertebrae’

dogoyna          ‘now’

koomam          ‘rat’



1. mirkitin   ‘greets me repeatedly’


2. mirkutu    ‘greets him repeatedly’

mirkutnu   ‘greeted him repeatedly’


3. mirka   >   mirkǝ  ‘greet her’

baadu   > bǝǝdu  ‘wash him’


4. cǝǝri   >    ciiri     ‘your head’

cǝǝru  >    cuuru  ‘his head’

ǝski  >    iski   ‘hear you’

ǝsku  >   usku  ‘hear him’

ǝske   > ǝski   ‘hear’   (rule 3 but not rule 4)

vǝǝge   >   vǝǝgi  ‘is emptying’

baadi   >   bǝǝdi   ‘wash you’


5. dǝbǝǝbǝr      ‘lizard’              OK

kaasow            ‘millet’             should be     kaasaw

kefter              ‘book’              OK

kupurki            ‘male goat’        OK

gadaamo          ‘horse’             OK

cǝcerkǝ            ‘vertebrae’       should be   cecerkǝ

dogoyna          ‘now’               OK

koomam          ‘rat’                 should be    koomom


The Kera manage all of these rules effortlessly (plus a few more not mentioned here!) It is amazing how complex a system can be, yet speakers still cope. Having said that, linguists like to get behind these rules to see what the reasons for the changes are. In the case of Kera, it is probable that these vowel harmony rules are applied because vowel harmony shows what belongs to a single word, so when you hear a continual stream of sound, you can find the word breaks more easily (because within the word, all the vowels are the same or similar). That helps you to process what you are hearing. And that helps communication.


More information

Kera is a Chadic language spoken in Chad. More information can be found at:


Data and puzzle formation:  Mary Pearce

The Kera in this puzzle has been simplified (and vowel symbols altered slightly), so it would not be appropriate to quote anything from this puzzle in a linguistic publication. For information that can be quoted, please see the publication list in the Ethnologue cited above.