In order for people to participate in government, they need to be able to speak their minds so their voices are represented. Otherwise, they won't be able to make the changes need to improve their lives and increase their standard of living. So this is why freedom of speech and freedom of the press is important. The freedom of the press is effectively the written and broadcasted version of speaking out in the town square, more or less.
Despite the fact that there are freedoms of speech and press, there are limitations. The government can limit people from saying things to incite a riot or revolution to overthrow the government. This applies to treason and sedition. A common saying is "you cannot yell 'fire' in a crowded theater". Of course, if there is an actual fire then it's a different story. But creating a false alarm to incite panic is not allowed. Also, people cannot say untrue facts that are aimed to hurt another person or company. These are libel and slander, in which someone can be sued for damages. In addition, there are anti-obscenity laws to prevent people from saying and displaying various obscene acts. This leans more toward the media, but it also applies to general speech as well.
Freedom of speech is important because, in order to be able to say your thoughts out loud that other people not might agree with, you could use freedom of speech as an answer in order to be able to speak freely.
The government can limit free speech whenever you say something untrue or highly offensive to the government or other higher-up government forms.
