Fingilish is when people use English letters to write Persian words. It's like a secret code between Persians who speak both English and Farsi. For example, instead of writing "سلام" (which means "hello" in Persian), someone might write "salam". This way, they can write in Persian, but it looks like it's written in English. It's like writing your own secret language that only people who know both languages can understand. Even though it might look confusing at first, it's actually pretty simple once you get the hang of it!