Since language is the basis for communication between people, it is important to master it in order to acquire and develop communicational language competences. A child learns language from its very birth, and to what extent, depends on its surroundings. When a child begins a formal education at school, it will transfer speech into writing and will learn the language in order to fully master it. Language is taught and learned at Croatian language classes and has a special place as a separate teaching field. Language as a teaching field relies on several parent sciences for the content of the lessons, within which orthography is also taught. The basic task of orthography classes is to teach pupils how to write what we speak. Orthography is defined as a set of rules which determine the way of writing, and breaking of these rules leads to spelling mistakes. All the orthographic rules are explained in normative textbooks, and the most recent one was issued in 2013, entitled Croatian Orthography, published by the Institute for Croatian language and Linguistics. According to the Elementary School Curriculum (Ministry of Science, Education and Sports, 2006), the topics are defined that include orthographic lessons. Some of them include correct pronunciation and writing of the phonemes č and ć. Pupils come across the phonemes č and ć everywhere, including in their textbooks. In the Croatian language classes correct usage of the phonemes č and ć may be verified by means of dictation. Dictations have an important role in the process of practicing spelling, i.e. in determining the extent in which pupils have acquired orthography. This thesis explores whether pupils will spell correctly the words which they find more frequently in their textbooks, i.e. whether they will make more mistakes in spelling the words that are less frequently found in textbooks. A test dictation has been carried out for the purpose of the research.