What does it mean when someone calls an article scholarly, academic, or peer reviewed?
Who writes these articles?
Experts in their fields. Depending on the discipline, that could mean folks who work at universities or it could mean they work in their field (in a lab or practice, perhaps for the government).
Why do they write in these journals and not in magazines or newspapers or in books?
The most rigorous research happens in these journals. Publishing in these journals assures that your research will be read and cited by experts within your field of study. This research is the most up to date - once research is published here, it can be referenced for a general audience in newspapers or magazines, or it may be referenced in a more comprehensive work, such as a book. Having an article published in a journal is prestigious and may be a factor in getting and keeping one's job at a university. No, authors do not get paid by these publications.
How do I access these journals?
These journals are very expensive to subscribe to. UT subscribes to more collections than all but nine colleges in the country. You can search within the databases recommended on this guide.