Actually, Freedom of Speech is part of the First Amendment. The right to remain silent after arrest is part of the Miranda judicial decision. The Fifth Amendment deals with due process, including the right of defendents not to testify against themselves:
No person shall be held to answer for a capital, or otherwise infamous crime, unless on a presentment or indictment of a Grand Jury, except in cases arising in the land or naval forces, or in the Militia, when in actual service in time of War or public danger; nor shall any person be subject for the same offense to be twice put in jeopardy of life or limb; nor shall be compelled in any criminal case to be a witness against himself, nor be deprived of life, liberty, or property, without due process of law; nor shall private property be taken for public use, without just compensation.
Good Lord, this old can of worms again.
America and Europe have vastly different traditions in this regard, and I don't think it can be said that one system is better than the other. A valid criticism of the American system is that the term "freedom of speech" has been interpreted so broadly that it is almost certainly no longer what the Founding Fathers had in mind, and has been used to defend certain kinds of hate crime (the picketing of funerals by the infamous Westboro Baptist Church is an example); a valid criticism of the European system is that speech is so heavily regulated, that proper debate is becoming increasingly difficult (the new law against incitement of religious hatred, for example, has even been criticised by the very people it is designed to protect).
But even in the States there are restrictions on freedom of speech. The First Amendment covers only laws made by Congress, so you cannot invoke the First Amendment to force a newspaper to publish your letter uncensored, for example. And even in Europe, not everything is banned: there is no such thing as a law prohibiting moral damage, but there is a law banning the incitement of racial hatred. If I call somebody an offensive name, I can expect to be reprimanded; but only if I call on people to perform acts of violence against certain ethnic groups do I actually break the law.
All of this, of course, is quite irrelevant to the thread.