Informal experiences in mathematics often include playful competitions among young children in counting numbers in as many as possible different languages. Can these enjoyable experiences result with excellence in the formal processes of education? This article discusses connections between mathematical achievements and natural languages within the CLIL (Content and Language Integrated Learning) theoretical framework. The focus of the research study is set on learning counting and concepts of numbers in bilingual, German-Macedonian, context, in early primary school, taking into consideration students' previous language and immigrant backgrounds. In particular, developing number concepts is analyzed through children (un)awareness of the existence of a starting element in the set of natural numbers, a unique immediate successor and a unique immediate predecessor of any natural number (except for the first element) and the infinity of the natural numbers. The obtained results are discussed through two case studies on which the conclusions are derived.