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!”
