“JOHN happened. I used to live there. He visited once, I was pleasantly charmed because he was so'rough, I guess. Different from most Vault Citizens. (Sighs.) Of course, he let me try this little thing called 'Jet'...”— Leslie Anne Bishop
Learn about Vault City and education from Mrs. Bishop is an unmarked quest in Fallout 2.
Ask Leslie about Vault 13 or G.E.C.K. (either option is unavailable if you already found it) and end the conversation. She will offer you a drink (if you have 6 Strength or 6 Charisma). After you accept, she and the Chosen One will end up in her room. Have sex with her. Speak to her in bed about Vault City (requires Intelligence 9). She'll explain that she lived in Vault City and someday met Mr. Bishop, he opened the wonderful world of drugs to her, but when Vault citizens found out about it, they kicked her out and she had nowhere to go but to join Mr. Bishop. She took the Pip-Boy lingual enhancer with her when she left Vault City. If asked, she will give the Chosen One the code to her safe (used through the Lockpick skill on the safe) where the enhancer can be found hidden in a secret compartment.