Main Difference in Meaning
We can use 'someone' and 'anyone' interchangeably. But they do not have quite the same meaning.
'Anyone' as a pronoun means any person.
For example, imagine you would like help from a person, and you don't care who that person is, in this case, you can ask for help from anyone.
'Someone' as a pronoun means some person. As opposed to 'anyone,' 'someone' is a little more specific. But keep in mind that it still is some person "of unspecified or indefinite identity."
Main Difference: In Statements
In a question, both can be used, but 'any' is usually used in negative statements, 'some' is used in affirmative statements.
|I didn't know anyone who is British.||I know someone who is British.|
|She doesn't need anyone to help her.||She needs someone to help her.|
Main Difference: In Questions
'Someone' is more specific. When we use 'someone' in a question, we are subtly implying that we are sure there is a person responding to our question.
But 'anyone' is more general. It means we are asking a question without particularly expecting an answer.
In the first sentence, we do not assume someone will answer us. We're pretty sure there's no one there.
In the second sentence, we somehow are implying that we suspect somebody might be there.
Let's look at another example:
Here, you actually mean at least one person has touched your food.
This is a general question you ask a group of people, without any implications or hints.
When you want to talk about a specific person, but you still do not wish to say whom, instead of 'anyone', you should use 'someone', because it is more specific.
I'm going out with
Here, you cannot say 'I'm going out with anyone', because you are going out with a specific person.