Linguistic expression is native human need which is realized by written or acoustic signs. Although adoption of language requires much effort, children overcome it with easiness until the third year (Erdeljac, 2009). While children successfully adopt mother tongue, the situation changes when they start to go to school; it is expected that they communicate in Croatian language, but they often have mastered only the native idiom. One of more important aims of teaching the Croatian language should be development of communicative competence because it is a foundation in the early stage of learning. Children adopt new lexemes every day – when they have developed communication abilities and a larger vocabulary, they also understand and use new words faster. School period is a dynamic period of student language development and an enrichment of the dictionary depends on the different linguistic and extra-curricular factors. The most pronounced changes of lanuage are in lexis – their infleunce is visible in a Croatian dialects and also in the Croatian standard language (Brdar, 2010). The foreign words that are most commonly in use today are anglicisms. There are different explanations of Croatian linguists on anglicisms and why anglicisms are more and more present in Croatian language, especially in younger population. The purpose of this research is to explore the frequency of anglicisms in spontaneous and informal communication of younger school age students and sixth grade elementary school students. It is also investigated how the school that students are attending, age and gender affect on understanding and using anglicisms of younger school age students. In correlation to the focus point of this research we established three research questions/parameters we wanted to observe – do the age, gender and the school that students are attending influence of using anglicisms in communication and do students understand the meaning of the words given the different contexts of their use. Research has been conducted in Zagreb. Population selected to participate in the research consisted of the students in third and fourth grades of primary school and also was conducted focus group in which participated sixth grade students. The results have shown noticeable influence of student age on frequency of use anglicisms, while in school that students are attendning and gender there is some difference, but not noticeable. The results also indicate that students understand the meaning of some words only in context in which they use it.