The official websites (e.g., College of Engineering, Department of Computer Science) are rather ambiguous. To clarify, I post a short, clear description here. This is about TEOFL speaking score requirements for PhD in Computer Science at UIUC, which is the most surprising part during the admission process. Please check the official websites for other information.
- TA: you need a speaking score of 24
- RA: you need a speaking score of 22
- There are no other options. That is, if you don’t have a speaking score of 22 or higher, your chance of admission is zero.
Note that having a TA option significantly boosts your chance of admission. The above rule applies to almost every international student whether or not you have attended an undergraduate/master's program in the United States. That is, unless you are a US citizen who has lived in the States since you were born, the above rule applies to you almost without exception.