What is a scholarly source? A scholarly source may also be referred to as a peer-reviewed source. It is written by experts, for experts. They are reviewed by several experts before publishing. The opposite of a scholarly source is a popular source. It is something that is written using language the general public can understand. Examples of popular sources include magazines and news websites.
If you're unsure about a source, Google the journal title (ex. Journal of Speech, Language, and Hearing Research). If a journal is peer-reviewed, it will usually tell you so in the description.
When choosing an article:
Even if these appear in peer-reviewed journals, they are not peer-reviewed sources. These are opinions. Literature reviews are not the same thing as a book review.