Well, I know a little bit about this, but have the memory of a goldfish, so hopefully someone will write after me and fill in the probably many gaps.
The Bible is a combination of Hebrew, Greek, and Aramaic. We have none of the original texts, but many ancient copies with very few differences.
The Gospels, specifically, are Aramaic and Greek. Every watch "The Passion"? It was done in Aramaic, which was a common language in the area at the time.
Now, as the centuries and decades wore on, there was a obvious need to create a "canon" of scripture, similar to what the Jews had (our OT). As the years went by, it became difficult to tell which stories, books, etc. were real, and which were false. There was the problem of people changing and making up stories, and even writing letters and saying they had been written by other people.
Now, to put a stop to this, four criteria were used to create a final closed document that we call our bible today. The four Criteria:
-document had to be written by a disciple
-had to agree with the other texts
-(can't remember- I'll add them when I do. Sorry)
Well, it was compiled by bishop somebody (goldfish brain-fart), and we've essentially been using that original canon as our Bible ever since.
Now, you will find many other texts- look at the Catholic Bible- they have four additional books in theirs. Now, I do believe the Bible to be inerrant. I also believe that there are other genuine texts and stories of Jesus, but it can be hard to know, so be careful about how much faith you might put into what they say.
Anyway, somebody fill in what I've messed up. Otherwise, I hope I was useful.
Grace and Peace...