how a letter goes to a foreign country

     When you mail a letter, the stamp you put on it has been  purchased from the United States government. The United States Postal Service will take your letter anywhere in the United States, for the same price. If you want to send a letter to another country, the stamp costs more, but the money still goes to the United States Post Office. When our post office puts your letter on a plane, and it lands in a  foreign country, the post office of the foreign country takes your letter to its destination, at no additional charge to you. The person to whom you sent the letter doesn't have to pick it up at the airport. It is usually delivered to the address on the envelope. Our post office does the same thing when letters are sent from a foreign country to someone in the United States. A small but important example of international co-operation.

dead letters, dead languages, a morgue for articles

     A dead letter is a letter or some other piece of mail that the post office has been unable to deliver. It may be missing an address, and have no return address. The address may be illegible ( impossible to read ). This mail sits in what the post office calls the "dead letter office". The post office keeps it there for a while before discarding it. So put your return address on any mail you send. If the post office can't deliver a piece of mail, and it has a return address, they bring it back to the person who sent it.
     A "dead language" is a language that no one speaks. Like Latin or ancient Egyptian, it exists only in old books and museums. There are a few people who can read some of these languages. They became interested enough to study them, and can read the old books or tablets written in "dead languages". No one really knows what these languages sounded like, because no one alive can speak them.
     A newspaper "morgue" is a file room where a newspaper keeps copies of articles it has published in the past. If you wrote to the newspaper and told them what you were looking for, they would find it and send you a copy. Sometimes they charged for copying and mailing, but that's all. Now some newspaper archives are available online, and the custom of newspaper "morgues" is dying.