Teaching English using Duolingo application to improve student performance. (Supervised by Dahlia D. Moelier and Andi Hamzah Fansury). The background of this research is the fact that the students' opinion of learning English is bored and difficult to learn. The objectives of the study were to learn how to use the Duolingo application to improve students' grammar in English.
After conducting the research, the researcher concludes that using the Duolingo application to teach English grammar improves students'. The average score for the pre-test (before treatment) was 46.79 and in the post-test (after treatment) the students achieved a score of 64.36. Teaching English Using Duolingo Application to Enhance Students' Achievement.(Dibimbingoleh Dahlia D. Moelierdan Andi Hamzah Fansury).
INTRODUCTION
- Background
 - Identification of Problem
 - Restricting the Problem
 - Formulation of the Problem
 - Objectives of the Research
 - Significance of the Research
 
Most countries in the world have established language as one of the compulsory subjects studied in schools. Apart from the four skills, English has several aspects that can be taught to students. First, the comprehension of most students in English is a difficult subject to learn.
Second, the condition of students who lack vocabulary that will make them unable to understand when learning English. Learning English by using the application is one of the best ways to get them interested in learning. From the identification of the problems above, the author focused on improved grammar skills by using the Duolingo application on smartphone.
REVIEW OF LITERATURE
- Theoretical Review
 - Duolingo Application
 - Grammar
 - Interest in Learning English
 - Relevant Research
 - Conceptual Framework
 - Hypothesis
 
Hornby in Oxford Advanced Learner's Dictionary of Current English defines grammar as "the rules in a language for changing the form of words and combining them into sentences". So, the teacher should make the students interested in these two kinds of interest in the students' self. They said that interest affects the process of learning result, when a person is not interested in learning something, the result cannot be expected to be successful. the student with great interest in learning English will be more successful, and the result will be maximal than the student with little or no interest.
Students' interest in learning is influenced by several factors, including internal and external factors. In school education, the teacher should pay more attention to train and maintain students' interest in learning English. Possible solutions must be acquired to solve problems that appeared in the teaching and learning process.
METHOD OF THE RESEARCH
- Research Design
 - Time and Location of the Research
 - Population and Sample
 - Research Variables and Operational Definition
 - Instrument of the Research
 - Procedure of Collecting Data
 - Technique of Data Analysis
 
This question contains some of the respondents' questions about students' interest in learning English using the Duolingo app. Evaluation of the correct answer of the students in the pre-test and post-test using the following formula. The researcher makes a conclusion that students are interested in the Duolingo app to learn English.
This means that all students enjoyed learning English with the Duolingo app. From the table above, we can see that students are interested in learning English using the Duolingo app. This is evidenced by the average score of the students on the pre-test and post-test.
FINDINGS AND DICUSSIONS
Findings
This section discusses the presentation and processing of pretest and posttest data and student vocabulary improvement before and after treatment. In addition, the mean score of pre-test and post-test and questionnaire and standard deviation of pre-test and post-test are also further investigated as consideration in this research. The following table is the pre-test score of the students and the percentage of the experimental and control groups.
Source: Pre-test students Based on the data in table 4.1. the pre-test showed that of the 33 students not there students were rated excellent to very good. Before performing the treatments, the researcher was given a pre-test to know the students' prior knowledge. In addition, the purpose of the test was to find out whether the students had the same level or not.
After calculating the student's pretest score, the mean score and standard deviation are presented in the following table. Very good categorization was achieved by 5 students (15%), which is in the pretest, none of the students could get a category. Based on the description above, it is clear that there was an improvement in the students' English grammar after the test by treating those students who used the Duolingo application.
The result of the post-test was defined to be the way to know the mean score and standard deviation. It can be observed in the table above that the post-test was rated 64.37 for its mean score with the standard deviation obtained 14.878. It can be referred to from the description of the mean score and the students' deviation for the post-test.
It showed that the use of Duolingo Application significantly improves students' performance in learning English grammar.
Discussions
The first discussion is about improving students' grammar when learning English through the Duolingo app. The result of the post-testing shows that the use of the Duolingo application significantly improves the students' achievements. From the table above, we can see that the respondents liked learning English with Duolingo very much, and the respondents also liked learning English with Duolingo.
From the table above we can see that of the respondents were very happy to learn English using Duolingo application whenever they want where 20.61%) of the respondents would also like to learn English using Duolingo application , whenever they wanted. From the table above, we can see that the respondents said that the Duolingo application was a great help to them in learning English, where the respondents said that the Duolingo application helped them to learn English. The author concludes that the Duolingo application is very useful for students to help them learn English.
Meanwhile, they said they didn't complete one challenge per day on the Duolingo app. From the table above, we can see that 0 (0%) of the respondents chose the option 'Strongly agree', which means that none of the students liked learning English with the Duolingo application, where 3 (9%) of the respondents chose the option ' I agree', which means that some students did not like learning English with the Duolingo app. From the table above, we can see that 0 (0%) of the respondents chose 'Strongly Agree', which means that none of the students agreed that learning English with Duolingo is boring, and 0 (0%) of the respondents selected the 'Agree' option, which means that none of the students agreed that learning English with Duolingo is boring.
Which means learning English using Duolingo application will keep students from getting bored. Which means that students are going to like English because of the Duolingo application. From the table above, we can see that 1 (3%) of the respondents chose the option 'Strongly agree' which means that the Duolingo application cannot help them learn English and 0 (0%) of the respondents chose the option 'Agree' .
The use of Duolingo in teaching English could improve students' success in learning English, especially in English grammar.
CONCLUSION AND SUGGESTION
Conclusion
To measure students' interest in learning English from the Duolingo app, the researcher gives students the question. Students'. they have to answer the question whether they are interested in learning English or not. From the table above, we can see that 8 (24%) of the respondents were very fond of learning English, where 9 (27%) of the respondents wanted to learn English as well.
This means that all the students could enjoy learning English using the Duolingo application at any time they did not need to attend the class to learn English. From the table above, we can see that 4(12%) of the respondents were said that they strongly agree to finish a challenge per day in the Duolingo application, where of the respondents said that they agree to finish a challenge per day in the Duolingo Application. From the table above, we can see that 0 (0%) of the respondents chose the option 'Strongly Agree', which means that none of the students did not like learning English, where 4 (12%) of the respondents chose the option 'Agree '.
From the table above, we can see that the respondents strongly agreed that they would become English because of the Duolingo application, and the respondents agreed that they would become English because of the Duolingo application. From the first day the researcher introduced the title of this study, all students were curious about its application. But before the researcher deals with the students, the researcher must first take the pre-test to know the students' prior knowledge.
After taking the students' pre-test, the researcher introduced the Duolingo application and asked them to install the application on their smartphone. Another reason why the students were interested in this application is that students could learn anytime, anywhere in this application on their smartphone. A plus of the Duolingo application is that in this application when the students have answered the questions, the correct answer is communicated to them.
The students were interested in learning English with the Duolingo application, which was determined by the questionnaire that the students were given.
Suggestion
Improving students' speaking skills through talking board games of grade VIII of SMP N 13 Yogyakarta in the academic year of 2013/2014.