The differences of writing letters to different audiences are being affected by formality, grammar, choosing the content to be included on the letter and the approach of writing. Writing a letter to a friend is informal compared to writing an article to an editor. Informal in the sense that you can include in your letter whatever topic that comes out from your mind as long as it touches your interest. Experiences, meeting new people and involvement on activities in school are some of the ideas that you share to your friend without thinking the grammar, punctuation marks and periods. You can even add some jargons that makes your letter more interesting and sometimes makes your story funny.
On the other hand, writing a letter to an editor is formal in the sense that you must organize your ideas so that you can address your topic in the most convenient way that is straightforward and not confusing. In this type of writing, you need to consider your grammar, the approach of writing (opinionated, clamored on problems that occur or informative about a topic that is new to the reader) and the content of your essay (a very important aspect that covers the body of your article).
For me, writing in Filipino is easier compared to writing an essay in English because I can easily express my thoughts and ideas about a certain topic. Whereas in English, I need to think first what is the equivalent translation of my ideas so that the understanding of the main thought of my article will not be sacrificed. For example, telling a friend of how difficult it is to access food in where I am right now and what are the reasons behind is easier to draft in Filipino. In English, I still need to state the whole thought in a way that the reader will not misunderstood my main point.
Errors such as the spelling and grammar are being watched out of course if your writing an article and this is my weakest area in writing essays in English. I am very weak in using tenses and I always use words spelled differently but sounds the same like compliment versus complement, meet versus met and the use of has, have and had. But of course in writing an essay, I also formulate my ideas in English first but in times that I do not know how to express it in English, I then try to draft it in Filipino. Probably this is a good thing because you can easily asked help if you establish clearly what you really wanted to say and understand what you really wanted to share.
I think with constant practice and exposure to the community speaking pure English will later on improve my skills in writing, speaking and listening in English language.