Should I be proficient in English to be successful in GD?

Interview Preparation
#1

A candidate’s ability to communicate in English is unquestionably required. However, mastery of the local language is not always necessary or expected. The panel will be looking for you to be able to express yourself clearly and concisely. Don’t stutter or drag your words out. It is not necessary to have a large and sophisticated English vocabulary. On the other hand, you will be expected to comprehend what people are saying to you and to be able to respond appropriately.