They checked basic communication skills and clarity of speech.
Two telephonic round ,one with IVR in which they checked for vocabulary, pronunciation,voice clarity and presence of mind.
The tough one was they checked for MTI which is mother tounge influence while communicating in English,and the other round was with HR(human resource).
Firstly they analysed the score of IVR then judged personally on mother tounge influence.
While giving interview one should be clear and crisp while talking and presenting your idea or thoughts.
Gaps or fillers should be avoided as much as possible.