[Grammar] Analysing sentences

Hello, I need help! This is my main sentence (analysed on the clause level):

It was claimed that only man could use language as a medium of communication.

So far I have this suggestion:

It - Anticipatory subject
was claimed - verb
that - direct object
only man - indirect object
could use - verb
language as a medium of communication - adverbial? subject predicative?

I am stuck. I suppose I am thrown by the length of the sentence.

And what happens if we put 'the' in the sentence?

It was claimed that only the man could use the language as a medium of communication.

I appreciate any help!
- Anja.

[Soup]

With anticipatory constructs the true subject (also known as the notional subject) comes after the verb:

Ex: That only Man could use language as a medium of communication was claimed (by...).

Subject
Verb

It <subject>
was claimed <verb>
that ... <object; notional subject>