Forget to write it earlier but make sure to do well in your TOEFL/ IELTS or any other English Proficiency that you gave specially the Speaking section (aim for at-least 26 and try to get as close to the perfect score as you can i.e. 30) the reason being Professor’s look at your \textcolor{red}{\text{English Proficiency Test Oral Scores}} while selecting for TA’s (Teaching Assistant).
\hspace{20mm} Sure, they sometimes make exceptions but if you’re applying to a competitive branch then there surely be large pool of talented people and you don’t wanna miss the opportunity just because you had a lower speaking score!
For people who already are done with the test and applications : Be sure to keep this in mind and talk to your professor regarding the same! (They may tell you take the bridge English courses at the university or Professor may themselves asses your communication skills etc… )