A free program for Android, by Translator Text Voice Translator.

Hindi To Bengali Translator is a free app for Android devices that allows you to translate from Hindi to Bengali and from Bengali to Hindi. It is a simple and intuitive tool that can be used for translating a wide variety of text documents, emails, and messages. The app is designed to be used as a tool for translation and not for learning the language. 

The app is very easy to use and can be downloaded and used on any Android device. It is a completely free tool and does not require any kind of registration or subscription to use it.