So far as you are able to convince the officer that you have a good knowledge of the language, that's OK. If you are from an English speaking country or your national language is English, you can write a letter explaining that. The down side is, you have to rely on the officers will. So imagine what the result would be should the officer have a bad day just like any of us. What I personally recommend is to take the test, then you will know exactly how many points you will get for English. Even though I come from an English speaking country, I took the test just to avoid the hassle of having to write a letter to demonstrate my proficiency.
Nuff respect!!