The Croatian standard language is the standard language of society and culture. The norms derive from the basis on which the literary language is built, for the Croatian northeastern and literary traditions. The standard norm does not determine what in language can and which can not exist, but it determines what is in the language neutral, unmarked style, and what would be good to replace with another expression. Normation can be spontaneous and consciously, and usability and abstraction norms differ. In this work, within the theoretical framework of normativity and glasa jata in Croatian, the relationship between explicit (codified) norms and actual usage norms is examined. In the experimental part, a survey was conducted on the use of jata behind the covered r, as well as about the knowledge of the rules of writing ije/je. The results indicate that respondents are more inclined to the forms pogreška, strelica, krepak, istrebljivati, crjepovi, uvredljiv, privređivati, trjezniji, brjegovi, vrjedniji, ždrjebad. Likewise, respondents have shown that they make many mistakes in writing the words with ije/je.