He is a scholar and so probably can speak Latin, although it is Hamlet who actually says a line in Latin ("Hic et ubique")
He is a student. "Horatio, thou art a scholar. Speak to it!"
He tells Horatio to "draw his breath in pain," to tell Hamlet's story.
"Never to speak of this that you have heard", by which he means the appearance of the ghost, although Horatio heard nothing from the ghost's lips. Also, "How strange or odd soe'er I bear myself . . .that you, at such times seeing me, never shall . . . note that you know aught of me." Horatio and Marcellus are not to suggest even that they have an idea why Hamlet is doing what he is doing.
Hamlet is under a lot of pressure to hide his emotions and put on an act for people. Ophelia pushes his buttons in such a way that he explodes and all of that emotion is set loose, causing him to speak to her in a vulgar manner. This scene was put in the play to show how well Hamlet can hide his true feelings, but also illustrate that it is a matter of time until he snaps.
Marcellus and Barnardo assume that Horatio, being an educated man, will have studied Speaking to Ghosts 101 at Wittenberg University and will know how to talk to it.
He is a student. "Horatio, thou art a scholar. Speak to it!"
Horatio
Marcellus thinks that Horatio may know how to speak to a ghost because he is a University Man. I guess Marcellus assumes that's the kind of thing you learn at a University.
He tells Horatio to "draw his breath in pain," to tell Hamlet's story.
Yes the ghost only speaks to Hamlet. The others can see him but cannot hear him. When the ghost visits Hamlet in his mother's closet, his mother can neither see nor hear him.
"Never to speak of this that you have heard", by which he means the appearance of the ghost, although Horatio heard nothing from the ghost's lips. Also, "How strange or odd soe'er I bear myself . . .that you, at such times seeing me, never shall . . . note that you know aught of me." Horatio and Marcellus are not to suggest even that they have an idea why Hamlet is doing what he is doing.
The language spoken by archaic people varied depending on the time period and location. Examples include Proto-Indo-European, Proto-Indo-Iranian, and Proto-Semitic among others. These languages evolved into the modern languages we know today.
Hamlet is under a lot of pressure to hide his emotions and put on an act for people. Ophelia pushes his buttons in such a way that he explodes and all of that emotion is set loose, causing him to speak to her in a vulgar manner. This scene was put in the play to show how well Hamlet can hide his true feelings, but also illustrate that it is a matter of time until he snaps.
Marcellus and Barnardo assume that Horatio, being an educated man, will have studied Speaking to Ghosts 101 at Wittenberg University and will know how to talk to it.
They have no reason to speak Yiddish. It is or was the main language of most Ashkenazi Jews and is largely based on archaic German.
There is no 'narrator of the play". In some plays we see actors doing the actions while a narrator tells us what is going on. Our Town, for example, or anything written for Grade Two students. Hamlet is not that kind of play. Hamlet does have a special friend in Horatio, in who he confides, which makes him a confidant (unless he is being played as a woman, in which case she would be a confidante) and who he asks, as he dies, to "tell my story". Horatio asks Fortinbras to "let me speak to the yet unknowing world how these things came about" and Fortinbras says "Let us haste to hear it", but the play ends before Horatio narrates anything, mostly because we have seen everything which has happened and it would be boring to hear it all again. (That didn't stop Shakespeare in plays like Cymbeline or Twelfth Night, however.)
Hamlet - questioning the meaning of life