This study aims to identify the independent learning processes used by Japanese language learners to enhance sentence intonation. However, different intonations are required to express different intentions, such as declarative and interrogative sentences. The experiment of pronouncing sentences in conversational form has been done before, but too much data has been challenging to analyze using the OJAD (Online Japanese Accent Dictionary) website. The following three outcomes have been discovered through experiments using three approaches. First, without the help of audio examples and visualization of intonation, students can only pronounce sentences with flat intonation in both sentences from the pronunciation experiment per sentence for declarative sentences and invitation sentences. Second, there was an improvement in intonation in the two sentences due to the shadowing technique experiment, but it did not last long. Third, the experiment of adding information to visualize the intonation curve after the audio has played has shown that it is easier for students to pronounce sentences with the correct intonation. Furthermore, the correct intonation can be mastered by students relatively stable. The results of this study indicate that Japanese textbooks or learning media could also include audio and a visualization of the intonation curve so that students can pronounce Japanese sentences correctly, depending on their meaning.