Improving one's language skills normally includes both written and spoken language, where the latter is usually worse for learners as compared to the former. There are many psychological and interpersonal dynamics in conversation that are comparatively less for writing, even writing on public forums such as this one. While being literate in a language isn't essential for spoken fluency, it certainly does help. These are independent skills.
As an example I'm rewriting your own profile introduction here with certain changes:
<em style="color: rgb(0, 102, 204);">Hello! I am Gauri, currently studying to be a dentist. I want to improve my vocabulary and fluency in English. We have many languages in India but Hindi is the most commonly spoken language in all regions, apart from English to various degrees. I shall have to deal with a wide variety of people with different cultural backgrounds and languages in my profession, where English would be an asset. In my opinion, English is necessary these days because it is the global language of business communication and the most common lingua franca.</em>