The paper emphasizes the importance of nurturing the native language, but also that the adoption of a language standard whose adoption is one of the fundamental goals of teaching the Croatian language should not be neglected. It is the teachers who have a crucial role to play in this, because the teacher needs to know and respect the student's native idiom, while enabling him to use standard language. Teachers also have an important role to play in developing communication competencies. The paper examines the attitude towards the native and standard idiom among 4th grade students in the city of Sinj and the fluency of their speech. An analysis of the discussions in three classes of the Croatian language found that students, unless explicitly told that they must express themselves in a standard idiom, mix standard and native language. The analysis of different linguistic elements established that the native idiom prevails in relation to the standard. The mixing of native and standard indicates students' awareness of the importance of using the standard Croatian language within the school. Although the vernacular of the student is dominated by the native idiom, the analysis of certain components of fluent speech has identified a number of disfluencies. This fact can help teachers to continuously work on improving students' speech fluency by noticing student mistakes.