The vocative is a noun used to address someone. In English the vocative may be:

“Hey you!”, “Guys!, etc.

Basically the vocative is a modified form of the nominative.

Here are some examples in Hindi:

भाइयो और बहनो ! (Brothers and sisters!)

लड़को ! (Boy!)

बच्चो ! (Kid!)

 

The common ending for all three vocative endings was ो

 

Now take a look at these vocatives:

 

हे भगवान ! (O Lord!)

 

हे राम ! (O Raam!)

 

You’ll notice that हे serves as a sort of prefix. In English, this हे would mean “O” as in “O Lord”. The particle हे is commonly used before words borrowed from Sanskrit.

 

Now take a look at these sentences:

 

ऐ लड़को ! (Hey, boy!)

 

ऐ भगई ! (Oh, mister [brother]!)

 

When the particle ऐ is placed before the noun, this can give the effect of “hey!” or “oh!”