<p>Not the most qualified person to answer this but I will try.</p>
<p>First, check the requirements of the state(s) you plan to teach in because requirements do vary. Subjects that you can be certified to teach usually involve a core of education courses followed by a number of hours in a specific subject. You can move from state to state but requirements vary - could be easy or difficult.</p>
<p>A huge part of this is supply and demand. Some positions are extremely competitive, while other schools are just happy to have anyone that can halfway teach something like, say, Physics. But being fully certified looks good for the school and can mean more money for you.</p>
<p>For Virginia at least, you have to pass a subject test with a certain score in order to teach a certain subject, so majoring in creative writing or journalism and teaching English is very possible as long as you are still knowledgeable enough in general English.</p>
<p>Generally speaking most colleges require you to do student teaching in the subject you want to teach. This would make getting certified to teach both a little more difficult.</p>
<p>On the other hand in a lot of states if you get certified in one subject area you can still teach another as long as you a) pass the praxis for that subject area and/or b) don't have more than a certain maximum percentage of your schedule in the area in which you are not certified. (does that make sense?)</p>
<p>You don't necessarily have to take the PRAXIS. Some states have different tests. I know that California and Texas require different tests. I believe that Virginia also has different ones. The PRAXIS tests are usually much easier than the others. You can major in anything and teach any subject. You just have to get a credential and pass the test for any subject you wish to be able to teach.</p>