Absolutely! We have students who do not speak Serbian nor English and they can cope just fine. How?
English Club method is based on learning the language the same way kids learned their mother tongue. All the conversation is held in English – adapted to their age and abilities – and very little Serbian is used even with the kids who are native speakers of Serbian. Very soon, children learn to focus on what they know and have learned and to utilise their language skills. Over time, naturally, their vocabulary expands and they become more and more fluent in English, so there is no need for them to use Serbian (or any other language) at all.