Dr. Rajesh Ramayan (Kuyal Nayyar) "Raj Koothrappali" on the "Big Bang Theory" is an astrophysicist of the Physics department at Caltech (California Institute of Technology) where his three friends, Howard Wolowitz (Simon Helberg), Leonard Hofstadter (Johnny Galecki), and Sheldon Cooper (Jim Parsons) also work. Raj is in the USA with a working visa since he is actually Indian and never wants to go back to India because he dislikes the Indian culture and food. His favorite food is hamburger, although he is not allowed to eat it because eating beef is considered a sin in indian culture).
Raj's inability to speak to women is diagnosed by Howard's mother as selective mutism, which makes it even worse. Even though he is perfectly able to speak to his mother or sisters, he can't say a single word in front of another woman, which makes it impossible for him to have any romantic relationships. When Penny (Kaley Cuoco) is around and he really needs to say something, he whispers in Howard's ear so that Howard can say it loud. One time Raj accidentally uttered the words "good story" to the surprise of his friends, but he immediately stopped talking and placed both his hands over his mouth when he realized Penny was there.
The first time he did speak to Penny was when he discovered a planetary object beyond the Kuiper Belt (which he calls Planet Bollywood), causing him to appear in People Magazine's "30 under 30 to Watch", making him a local celebrity. He also got a larger office as a result of his discovery, in addition to that he celebrated at a party with Penny as his guest.
At the party Raj discovered that he can speak to women when he is drunk, although he becomes very self-centered and obnoxious. He even tells his parents that Penny is his girlfriend when they get back to his apartment that night although both his parents and Penny get mad at him because of this. When he is sober again, he tries to say sorry to Penny through a note, but she forces him to say "sorry", loudly.
Once Raj realizes he can talk to women when he's drunk, he starts a conversation with an attractive woman on a train. He does it so smoothly that she starts licking him; but when Howard tells him his beer was non-alcoholic Raj stops in the middle of the conversation and runs away.
Raj frequently communicates with his parents in India via webcam. When they get judgmental, he brings them into Sheldon and Leonard's apartment, leading to an argument between his parents and Howard's mother since the latter did not believe that Outback Steakhouse did not exist in India.
"Leonard wake up! You're missing some very excellent superhero quips!"
"Come on! You know I can't talk to women unless I'm lit up like the Hindu festival of Diwali!"
"I'm going to be deported, sent home in disgrace, exposed to the sardonic barbs of my cousin Sanjay, or as you may know him, Dave from AT&T customer service."