Nich pratyayas are used when one gets things done through someone else.
prerakatve nich.
adding nich to a dhAtu ((root) creates a new dhAtu.
paTh + nich = pAthati
pathati + nich = pAthayati.
This formula holds good for all dhatu vargas barring the 10th (churadi gana) - the 10th varga dhatus are already nich (ed). chorayati, tadayati etc
Atmanipadi root + nich some times results in new Atmanipadi (आत्मनेपदी) dhatu but always results in a parasmaipadi (परस्मैपदी) dhatu.
lokathe + nich = lokayate (may not be true for all the atmanaipadi dhatus) however it will for sure have a form like this - lokhayati
some examples
pachati + nich = pachayati
(gets cooking done)
dhAvati + nich = dhavayati
(makes one run)
bhavati + nich = bhavayati
kAdhati + nich = kadhayati
pashyati + nich = darshayati
bungte + nich = bojayati
it is easy when we look at nich this way. Forming sentences with this is a little tricky thing - there are elaborate rules for it
bala: patham pathati - boy reads
adyApika bAlam pAtham pAtayathi - teacher teaches the boy
adyapikA is the main doer = preraka (initiator)
Bala (boy) is also a doer however a minor doer (prerita - instigated)
We can see that there are two words in dviteeyaa bAlam and patham (we usually get two karma padams only when the dhatu is dvikarmaka - nich is another situation where we see this double karma padams)
bala: annam bungte = boy eats
mata balam annam bojayati = mother feeds the boy
bala: pachati = boy cooks
mata bAlam pAchayati is wrong usage
mata bAlena pAchayati is right usage
This is because -
Only gatyartaka [ dhatus that mean movement) , budhyartaka (dhatus that have some connection with knowledge), shabdavachaka (dhatus that mean making sound), akarmaka (dhatus that do not have karma), ashlishtadi padams (a series of dhatus starting with ashlisyati) take the dviteeyaa. All other instances it takes triteyaa.
If we are not careful enough a sentence involving nich may become a meaningless and funny sentence.
can we spot the mistake in this sentence
i send you a letter
aham bhavantam patram preshyAmi