It is time to have a first look at these personal pronouns. They are very important in English and we use them all the time (there are 3 in this sentence).
Here is a story full of third person personal pronouns:
John went to Susan's last night. He had flowers for her because it was her birthday. At her house he gave them to her and then he gave her a kiss. He took her to her favourite restaurant. They enjoyed it very much.
If you don't use personal pronouns it looks like this:
John went to Susan's last night. John had flowers for Susan because that day was Susan's birthday. At Susan's house John gave the flowers to Susan and then John gave Susan a kiss. John took Susan to Susan's favourite restaurant. John and Susan enjoyed the evening very much.
I think you can see that the first version is better...but imagine the conversation between John and Susan using no personal pronouns:
John: Hi Susan, how are...erm...oh, how is Susan?
Susan: Hi John, I...oh erm, sorry...Susan is fine...
John: I...oh, John got these flowers are for...Susan...
Susan: Oh, the flowers are lovely! Thank...John..
It is impossible...if you don't want to sound like a caveman!
We have personal pronouns for the first person - if I want to talk about myself; for the second person - if I want to talk to you and the third person if we want to talk about someone or something else.
There is also a singular form for one person or thing and a plural form for more people or things.
And they come in nominative, accusative and genitive forms!
(English is Easy! Remember?)
So the nominative (i.e. for the subject of the sentence) personal pronouns look like this:
he, she, it
It's not that bad is it?
You can find the full set here
In the dialogue above, between John and Susan, I think you can also see the evolution of the language. You can imagine primitive humans thumping their chests and saying, "Caveboy John like cavegirl Susan!".
The first and second personal pronouns were invented later perhaps.
Little babies also use the third person when they are just starting to speak.
When my younger daughter Biddy (her nickname) was very little she used to say:
(I am feeling a little hungry)
"Biddy DON'T shoesson!"
(I would prefer not to put on my shoes just now thanks)
(Erm, I have just done a poo and it is rather stinky!)
Not perfect English but we knew what she wanted!