Your textbook is in English. Your teacher explains in Bangla. Your exam script will be a mix of both. Most tools that claim to work in Bangla ignore all three: they either show you a translated interface while the teaching still happens in English, or they run an English answer through a translation pass. Both fail the same student for the same reason.
The transliteration problem
Ask a general-purpose model to explain অন্তরীকরণ in Bangla and it will faithfully translate 'derivative' into a Bangla coinage. That word is correct. It is also not the word in your textbook, not the word your teacher says in class, and not the word printed on your question paper. The lesson is now in your language and disconnected from your course — which is worse than useless the week before an exam.
A translated lesson a student can't map back onto their syllabus is worse than an English one.
What Porphy does instead
The lesson is written in Bangla, and technical terms are held in English by a glossary term lock — a constraint applied to every writer, not a polite suggestion in a prompt. So a paragraph reads as Bangla prose with 'derivative', 'tangent' and 'adiabatic' sitting inside it, exactly the way a teacher says them at the board in Dhaka or Rajshahi.
- The voice tutor speaks Bangla out loud — a native-audio model, not text-to-speech read over a translation.
- Nine tutor voices, each with a Bangla sample you can play before you pick one.
- Research is not restricted to Bangla sources: it reads the best material in any language, then teaches you in yours. Most good physics and chemistry material online is in English; there is no reason you should have to be.
- Formulas and diagrams render the same in both languages, including Bangla labels inside a diagram.
Why this was harder than it sounds
Bangla and math do not coexist quietly. A price like ৳100 collides with the dollar signs that delimit LaTeX, so a naive renderer turns half a paragraph into an equation. Bangla inside a formula label breaks the formula. And a speech model that has not been pinned to Bangla will happily decode it as Hindi, since the scripts are related. Each of those is a specific fix in the product, not a setting somebody ticked.
The demo at the top of the homepage has an English / বাংলা toggle. Switch it and watch the same lesson, the same whiteboard, the same tutor — in Bangla, with the terms left alone.