English is the most taught language across the globe. In countries like India, many schools use English as a medium of instruction or teach it as the second or the third language. Thus, many people are acquainted with the language to a certain extent. It is not necessary that people who perform exceptionally well academically in English are good with spoken English as well. In fact, there are many who can write flawless English easily but find it very difficult to speak in English. There could be many reasons for this.
The luxury of time
While writing, you have the luxury of time to think and write leisurely. You can find yourself correcting your sentences or grammar leisurely. Also, there are many tools available online that can help you correct your grammar and sentence construction. This luxury is usually not available when you are speaking. In fact, within a few seconds you need to give a reply or make a conversation when you have a listener. With a listener or an audience, you need to be very quick in thinking about a response and putting it across in a meaningful way.
Your listener or audience can make a difference while speaking
Speaking to a friend or someone in a relaxed and informal situation could be very different from interacting with someone in a more formal atmosphere. This can also create a huge impact on your ability to speak comfortably in English. This could be due to anxiety or pressure to perform well.
How you started with English
If you started learning English in school in the conventional method where there is more focus on grammar and written English, you become good at it. There are many exercises and worksheets that you practice and can be excellent in expressing yourself through writing.
If you heard English right from the time you were born or started learning a language which starts at home, you can become good at spoken English.
It is more about what you were exposed to and how you got introduced to the language.
Use of the language
There are many who are well educated and scored really well in English. However, if you work in a setup where English is used for written communication whereas, for verbal communication, it is the local language that people prefer, then your ability to speak well in English could be very limited.
This is again an area that needs a lot of practice and effort. A limited vocabulary is good enough for regular small talk and general day-to-day business. Good vocabulary is not just limited to a few hundred words but includes idioms, phrases, and even slang that is used by many. Again, while writing you have the luxury to think about different words and even find synonyms or idioms through various tools available online which is not the case when you speak.
So, what can you do?
To be able to master spoken English or any other language for that matter it is important to speak in that language as early as possible. The fear of mistakes or being mocked is what stops many people from talking in English. Muster courage to overcome that fear and speak whatever you know. As you speak you can build on what you already know and improve your spoken English over a period of time.
You can even take help from online language courses that are known to assist you with your conversational practice.