It would in no way hamper free speech, just as requiring a lawyer to have a degree and license hasn't restricted a persons right to legal counsel.
A lawyer's requirements to practice law are the guarantee that he is properly educated in the law, same with doctors. Granted the stakes aren't quite as high for journalists, but nor does the barrier of entry have to be made as high.
The basics of how to be a Journalist with integrity should be taught and set as a standard, what those actually are, i'll leave to someone else to define, but putting an end to quoting anonymous sources i'd say is the starting point.
You can't be serious. Licenses for law and medicine impede freedom. They limit our choices of (and the cost of) legal and medical services. We are just willing to make this trade off because average people have a hard time determining the quality of these practitioners and we don't want people going to jail or dying in surgery because they aren't very smart consumers.
You can't "improve" speech without making it less free. Sometimes the loss of freedom is worth it (like yelling fire in a crowded room) but most of the time it is not worth it. Restrict our freedom of speech so that journalists can't use anonymous sources? Give me a break.
"I'll leave someone else to define [the standard]." That's convenient, since there is no standard that would be enforceable without being oppressive. I challenge you to come up with a standard that would solve the problem you state, that would be enforceable, that wouldn't be an insult to basic freedoms of speech. You also have to define what a "journalist" is. In the internet world, we are all journalists.
I dont see how requiring credentials for a job in any way affects free speech. I'm not saying you cant write something down if you dont have a license, if you want to start a blog, magazine, newspaper, etc without a license on you go, write whatever the hell you want.
Its about setting standards and showing that you have a seal of approval from a governing body. Think of standards compliant HTML/CSS and the W3C, it sets the standard, but you're completely free to ignore it and write bad markup, but it'll be recognised by your peers that you dont meet the standard. THATS what i'm talking about.
THAT wasn't clear. Both of your examples, law and medical licenses are legally required.
Journalism schools already teach ethics and offer certificates. Reporters already are members of organizations with ethics statements:
http://www.spj.org/ethicscode.asp
All I'm saying is legally requiring some sort of enforceable code of conduct for journalists before they can work is a violation of free speech.
If the idea i'm talking about was implemented, i'd define a Journalist as someone that has a degree and a license. Whether they are a guy with a blog or a nightly news anchor. The lack of definition right now is the kind of thing i'm talking about.
A lawyer's requirements to practice law are the guarantee that he is properly educated in the law, same with doctors. Granted the stakes aren't quite as high for journalists, but nor does the barrier of entry have to be made as high.
The basics of how to be a Journalist with integrity should be taught and set as a standard, what those actually are, i'll leave to someone else to define, but putting an end to quoting anonymous sources i'd say is the starting point.