Leetspeak is the language of the Technopunk, the sub-culture of underground Georgetown. In order to learn Leetspeak, you must carefully follow a few steps. But be warned: it may take a LONG time to learn leet, even if it is only 36 pieces of code.
How do you learn leet? You learn leet by visiting Cafe Giardia and talking to Pierre. He will ask you to go pick up parts at the Junkyard. The part you take back to him might or might not be junk (its very random). If Pierre decides its not junk, he will take it and you will learn a letter of leet. Do this every day until you have learned all letters of the alphabet (A-Z) and all the numbers (0-9). What is the point of leet? Once you have learned leet, you can cook Syn at Lee Hwon Fook. It takes 40 motivation to cook one Syn.
What is syn used for? Syn is used to make Oppia's at Chem Chemical in Georgetown's Industrial Place, which you can sell or use to get the Exp+ attribute.