Chrome doesn't do this though, its translation requests are just sent to Google Translate for processing (which obviously includes the data you want to translat

Chrome doesn't do this though, its translation requests are just sent to Google Translate for processing (which obviously includes the data you want to translate). This is offline and thus more private. It might be a little challenging to get it on mobile given that this is machine learning and so obviously needs some processing power though I don't know the requirements.