You need to inform your writers of the type of language style they should be using when writing the articles. If your article writing service is going to be writing on a casual topic then their language style needs to reflect this kind of topic. You might want to give them ideas about the kind of language styles they should be using throughout the project. Factual and academic writing should be reflected in a formal and academic tone and it might be a good idea to choose writers who naturally write in this type of language.

Tone is very important in an article because it allows the reader to get a feel of what the article will be about before they read the entire article. Different readers enjoy different tones when they are reading an article and alternating your tones between articles will help you to relate to a larger audience. The most important facet of the tone, however, is that it be as natural as possible.