"English" is straightforward—it refers to the English language. "Samsarikkan" probably means to teach or explain. "Oru" means one. "Formula" is obviously formula. "Free free pdf" refers to getting a PDF document for free.

What's the most effective formula for learning English? It's usually a combination of vocabulary, grammar, and practice. But since the user wants one formula, maybe I can condense it into a daily routine or a specific method.

First, I need to consider the user's needs. They might be a student or someone looking to improve their English, especially if they don't have much money to spend on books or classes. The key here is providing a simple, effective formula that can be applied daily without any cost.