The Toba are an indigenous people in Argentina, Bolivia and Paraguay in what is known as the Gran Chaco region. In Argentina they live mainly in the provinces of Chaco (not to confuse with the region), Formosa and Santa Fe.
Their language uses a set of particles to denote presence as well as to denote motion or act as classifiers. Most common particles are: da 'extended vertically classifier', ñi 'non-extended tridimensional classifier', yi 'extended horizontally classifier', na 'in motion, proximity', so 'in motion, distant', ca 'imperceptible, absent classifier'. How do we use these particles? An example would be,
qaica ca pan
EXneg CL:aus bread
'There is no bread.'
The first word literally means 'there isn't, doesn't exist' and it is followed by the absence classifier ca. Not only one must negate the verb but also the classifier must agree. On the other hand, we have the positive of this sentence,
huo'o na pan
EX CL:prox bread
'There is bread.'
Here we see the existential verb followed by the proximity classifier, indicating that the bread is there nearby. The classifiers, as seen above, can also indicate the shape of the object or if it either in repose or moving, I find this a very interesting feature of the language. But what would happen if you wanted to ask, unknowingly, if there is bread or not,
huo'o ca pan ?
EX CL:aus bread
'Is there bread?'
The bread here has no apparent existence to the speaker and therefore the absence classifier is used, note that the existential verb is positive. To this question we might answer qaica ('there is not') if the answer is negative. The absence classifier can even be used with the verb to convey the sense of an irrealis mood, a supposed situation or a theoretical event in the future, as illustrated in the phrase,
cha'aye huo'o ca na'aq
conj. EX CL:aus day
'Because there will be a day...'
This is a very interesting construction that may help stimulate new ideas for language creation.