It's obvious that the answer is no. Fluent oral English is not a must for doing business with foreigners. The goal of communication is not to show how impressive our English is but to achieve communication and understanding with others. It's not necessary for experts in foreign trade to be perfect in English. We should know that English in countries other than the United States and United Kingdom is not always as good as we imagine. As beginners, we may feel scared of making phone calls to customers, but we shouldn't be afraid. In fact, many foreigners themselves are not fluent in English, and Google Translate can be enough for communication. They are also afraid of making mistakes, just like us. Therefore, it's not a big deal if our oral English is not good enough. What matters most is having solid professional knowledge, various techniques, and methods that can help us to secure big orders.