Anybody vs. Nobody
Both 'anybody' and 'nobody' are what we call indefinite pronouns in the English language. But what is their difference? Are they interchangeable?
What Is Their Main Difference?
The main difference between 'anybody' and 'nobody' is that 'anybody' is a non-assertive indefinite pronoun, while 'nobody' is a negative indefinite pronoun.
'Anybody' is a non-assertive indefinite pronoun. When we use 'body' (or any words formed by the prefix 'any') we are not sure (asserted) of the existence of a thing/person. We are referring to a random person out of an indefinite number of persons without holding any specific presuppositions in our minds.
'Anybody' in Questions and Negations
In interrogative sentences, when we want to genuinely ask questions about a person and we are seeking an answer, we use non-assertive indefinite pronouns. Because we do not the existence of a thing/person. This is the normal (or unmarked) way of asking questions in English.
Typically, negative sentences usually take non-assertive forms. It is the normal (or unmarked) way of a negative sentence.
I didn't see
'Nobody' is a negative indefinite pronoun. It shows absence of a person. Note that when we have 'nobody' in a sentence, the verb should not be in negative form, because negative pronouns have the ability to make a sentence negative. They do not any help.
'Nobody' in Questions and Negations
We cannot use negative words in questions.
Negative words are inherently negative, which is why they do not need another negative marker in a sentence.