172 | IJET| Volume. 7, Issue 2. December 2018 THE EFFECTS OF USING DUOLINGO TOWARDS STUDENT’S VOCABULARY MASTERY Hermariyanti Kusumadewi and Myta Widyastuti khermariyanti@gmail.com Indraprasta PGRI University, Indonesia Abstract. This research aim is to find out the effects of using Duolingo towards student’s vocabulary mastery. It also expected to enable tutors to utilize electronic media such as Duolingo to support more modern and exciting teaching activities such as mobile or web-based applications. This research is experimental research to find effects of using Duolingo (x) towards student’s vocabulary mastery (y) in controlled condition. The experimental method used is true-experimental design, the researchers used Post-test Only Control. The sampling technique used by the researcher is simple random sampling, which is the experimental class VIII consisting of 30 students, as well as the control class VIII composed of 30 students. The result of student learning English with media Duolingo's Android Application has a positive effect compared to conventional student approaches. Keywords: English Language Teaching, Duolingo, Vocabulary Mastery INTRODUCTION Education has a vital role in life. Fundamentals of a country are education, an opinion that states that the progress of a country is influenced by good education much to be true. As educators, we should pay attention to everything that can affect the world of education, in this case, of course, everything that supports the education world to be better. By educating citizens with useful science can build the country better, by inserting the values of skills in education such as communication skills through the use of technology. In today's world, people are required to speak foreign languages, because of the competition that will happen by itself in this era of globalization. In the digital age of technology like today, we as educators must be able to follow, and also, we could utilize technology to support activities in the field of education. With the rapid development of such technology, the technology can be used optimally for advancement in various aspects of life. In the world of technology, education is beneficial to support learning activities both inside and outside the classroom. The technology used wisely can help learning exercises become more effective, efficient, and creative. Many of the benefits of technology that can be used in the education world, for example with easy access to internet teachers or teachers can easily find teaching support materials through the internet; the material can be online articles, softcopy books, video and audio learning. As a teaching support medium, a lot of things that can be done by utilizing technology. Kusumadewi and Widyastuti 173 | IJET| Volume. 7, Issue 2. December 2018 Learning a foreign language is not so tedious and troublesome through the internet software to be the most accessible platform, lots to avail and reach, such as Duolingo. Duolingo.com/id is one that will help us more proficient in foreign languages. Duolingo deliberately carry the concept of "playing while learning" to make it more fun and easier to use by all ages. Not only English can be learned through Duolingo, because Duolingo also provides a variety of other languages (Indonesian, Spanish, French, Italian, German, Portuguese, and Dutch), so we can learn all the language options provided by Duolingo. As the reasons have mentioned above, this research aim is to find out the effects of using Duolingo towards student’s vocabulary mastery. It also expected to enable tutors to utilize electronic media such as Duolingo to support more modern and exciting teaching activities such as mobile or web-based applications. Through this research, researchers want to find out the answer from problem formulation. Therefore, the hypothesis is “There is a significant effect of using Duolingo towards Student’s Vocabulary Mastery.” Previous research conducted by Ummah (2012, 111- 112) disclosed that many factors cause difficulty in learning Listening. The material is too fast, so students forget what they have heard. This study will be different from the previous because it promotes a new insight into the application of Duolingo for different grade of students. Thus the result could strengthen the previous findings. REVIEW OF LITERATURE Definition of Learning Media Learning media is a tool used by teachers to make learning happen effectively Sadiman (2006: 7). The media is anything that can be used to channel the message from the sender to the receiver so that it can stimulate the students' thoughts, feelings, interests, and interests in such a way that the learning process takes place. Furthermore, Asyhar (2012: 44) states there are four types of learning media, namely visual media, audio media, audio-visual and multimedia. Visual media is the type of media used only to rely solely on the eyesight of the learners, for example, non-projection visual media (objects of reality, portative models, and graphics), and media projection (PowerPoint and auto cad). Audio media solely on students' hearing senses, e.g: radio, sound cassette tape, and LPs. Audio-visual, i.e. the type of media used in the learning activities by involving hearing and sight as well as in a process or activity, for example: video cassette and frame film, d) Multimedia, that is media involving several types of media and equipment integrated in a process or activity learning, for example: TV and power point. In general, the benefits of using teaching media in teaching and learning activities are: (1) The teaching media can attract and enlarge the students' attention to the teaching materials presented, (2) The teaching media can overcome the different learning experiences of the students based on the economic background, (3) ) Teaching media can assist students in providing learning experiences that are difficult to obtain in other ways, (5) Teaching media can help the students' minds regularly develop about what they experience in their teaching and learning activities, such as watching a movie about an event or event. The sequence and sequence of events they witnessed and the screening of the film will be able to be studied on a regular and continuous basis. (6) The teaching media can foster the ability of the students to try to learn by experience and reality, (7) The teaching media can reduce the verbalism in a process (in the form of written or oral words) (Latuheru, 1988: 23-24). Student’s Vocabulary Mastery 174 | IJET| Volume. 7, Issue 2. December 2018 Based on the opinion of the experts above, the authors conclude that the types of media that can be applied in learning is very diverse. Teachers can use the media according to their needs. Regarding technological development, learning media can be grouped into two broad categories, namely the choice of traditional media and the choice of cutting-edge media technology (Seels & Glasgow in Arsyad, 2002: 33). It is further explained that usual media choices can be distinguished into (1) Projected visual visuals, eg projection of opaque, overhead projections, slides, and filmstrips, (2) Visuals not projected, eg images, posters, photographs, charts, graphs, diagrams, info boards, (3) Multimedia presentation, eg slide plus sound (tape), multi-image, (4) Visual projected dynamic, eg movies, television, video, (5) Print, textbooks, modules, programmed texts, workbooks, periodical, hand-out magazines, (6) Games, eg puzzles, simulations, board games, and (7) Realia, eg models, specimens (eg ), manipulative (map, doll). While the choice of cutting-edge technology media can be differentiated into (1) Telecommunication-based media, e.g. teleconference, distance lecture, and (2) microprocessor-based media, eg computer-assisted instruction, computer games, intelligence tutoring system, interactive, hypermedia, and compact disc. Definition of Duolingo Duolingo is a free language learning app created by Luis Von Ahn and Severin Hacker was launched in November 2011, and offers 68 different language courses in 23 Languages, with 22 additional courses still under development. Duolingo implements dictation and written learning, as well as speaking practice for users who have entered a certain level. Applications that can be used on iOS, Android, and Windows Phone is made in such a way that users can continue to improve the ability to discuss anytime and anywhere. Learning in Duolingo is designed like a game, to be attractive and easily absorbed. For the innovation, Duolingo was awarded Google Play's Best of the Best 2013 by Google because of the powerful gamification techniques used to get many people to learn new knowledge. Quoted from an article from The Guardian, Luis Von Ahn wanted to create a way to learn the language for free. "If you look at language learning in the world, there are 1.2 billion people learning a foreign language, and two-thirds of those people are learning English so they can get a better job and earn more. The problem is that they do not have equity and most language courses cost a lot of money. " Definition of Vocabulary Vocabulary is one aspect of language skills that are very important existence and very important also to be mastered. According to Hornby (2009: 1707) "Vocabulary is (1) the total number of words which (with rules for combining them) make up language, (2) word know too, or used by a person, in trade profession, etc.". While the Oxford Advanced Learner's Dictionary (2008: 1662) the vocabulary is "All the words that a person knows or uses. The notion of vocabulary was also presented by Richard in his Curriculum Development in Language Teaching (2003: 4) that "Vocabulary is one of the greatest things used linguists turned their attention to." So it can be concluded that English vocabulary (English: vocabulary) is a set of English words that are known by a person or other entity to declare an activity, objects, properties, and so forth. A person's Kusumadewi and Widyastuti 175 | IJET| Volume. 7, Issue 2. December 2018 vocabulary is defined as the set of all words the person understands or any words that the person might use to compose a new sentence. Furthermore, Nunan (1991: 117) says that adequate vocabulary is a key ingredient in the success of using the second language. Without mastering vast vocabulary, language learner cannot both producing and receiving the target language. Similarly, Richard and Renandya (2002: 255) state that vocabulary is a core component of the language proficiency and provides much of the basis for how well learners speak, listen, read, and write. Vocabulary is a core part of language proficiency since it has a big role in all language skill; speaking, listening, reading, and writing as well. RESEARCH METHODOLOGY This research is experimental research to find effects of using Duolingo (x) towards student’s vocabulary mastery (y) in controlled condition. The experimental method used is true-experimental design. In this design, the researcher can control all external variables that influence the course of the experiment. The researchers used Postes-Only Control Design (Sugiyono, 2003:85), where the values were compared before and after treatment. In this study, the treatment in question is the use of Duolingo towards Vocabulary mastery. Here are the designs used in this study: R x Q2 R Q4 Q2 = English learning outcomes of students taught using conventional methods. Q4 = English language learning outcomes of students taught with the Duolingo Application. Population and Sample In this study the total population of the number of junior high school students in the Omega Science Institute is160 students. Arikunto (2001: 118) Argues that the sample in the study is if the subjects are less than 100 people better taken all, so the research is population research. Furthermore, if the subject is more than 100 people, the sample can be taken between 10-15% or 20-25% or more. So, the sample is a representative of the population which aims to determine the average yield of an object. So, as a sample taken from class VIII students who will be used as an experimental class as many as 30 students, and class VIII students who will be used as a control class of 30 students. This is because, in an experimental study to ensure the validity of the data, the number of respondents sought was not too much. The sampling technique used by the researcher is simple random sampling, which is the experimental class VIII consisting of 30 students, as well as the control class VIII consisting of 30 students. The research variable is everything that becomes an object in a study, in this study two research variables are used, namely: Independent variable Free variables are variables that influence the appearance of a symptom. The independent variables in this study were students who studied using conventional methods and students taught with the Duolingo application; Dependent variable the dependent variable is a variable that is influenced by the appearance of a symptom. The dependent variable in this study was the result of mastery of the English vocabulary of junior high school students in the Omega Science Institute study guidance. This research uses three-angulation data: Observation, Experiment, Test. In this study, students are given a test using 20 multiple choice questions with choices: A, B, C, and D. This test is given before treatment (pretest) and after Student’s Vocabulary Mastery 176 | IJET| Volume. 7, Issue 2. December 2018 treatment (post-test) of learning English using Duolingo. Participants are expected to answer the question for 45 minutes. This test was taken from English module book of Omega Sains Institute. It is likely that with this test participants can improve their vocabulary mastery. In quantitative research, data analysis techniques used are precise, that is directed to answer the formulation of the problem or test the hypothesis that has been formulated in the proposal (Sugiono 2011: 243). The stages of testing research are as follows: In this case, the data collected from the study are presented in a simple statistical form, including by creating a table of value results, calculating class results by formulas, finding interval classes, determining class length, frequency distribution, mean, median, mode, and standard deviation. Before testing the hypothesis, based on the data collected from the results of this study, then use the Normality test and Homogeneity test. Afterward, the data of the student test score was calculated by using the t-test formula. Besides, the manual statistical analysis used to count the result of the t-test from the data. Eventually, the researcher concluded whether to accept or reject the hypothesis from the achievement of the t-test analysis. Based on the research hypothesis proposed, the statistical hypothesis is as follows: H0: µ1 ≤ µ2 H1: µ1> µ2 Description: H0 = there are no differences in the results of learning English between those who use the Duolingo application and those using conventional techniques. H1 = there are differences in the results of learning English between those using the Duolingo application and those using the conventional approach. FINDINGS AND DISCUSSIONS Control Group Learning Results (Students with Conventional Methods) From the answers of 30 students who are sampled groups of students taught by conventional approaches obtained the lowest value of 35 and the highest 85. After compiling the data, the Sturges’ rule was used to get the number of classes, class ranges and class lengths:Table. 1 Result of Conventional Group No X1 (X1)2 No X1 (X1)2 1 50 2500 16 40 1600 2 45 2025 17 55 3025 3 50 2500 18 40 1600 4 50 2500 19 60 3600 5 65 4225 20 85 7225 6 70 4900 21 60 3600 7 70 4900 22 75 5625 8 60 3600 23 55 3025 9 60 3600 24 60 3600 10 65 4225 25 70 4900 11 40 1600 26 70 4900 12 40 1600 27 50 2500 13 50 2500 28 55 3025 14 60 3600 29 35 1225 Kusumadewi and Widyastuti 177 | IJET| Volume. 7, Issue 2. December 2018 15 40 1600 30 65 4225 Jumlah 1690 99550 From the data above it can be analyzed the Mean, Variance and Standard Deviation as follows. Table. 2 Frequency Distribution of Conventional Group No Class Interval Absolute limit Mid- point Absolute Freq Relative Freq 1 35 – 43 43,5 4 39 6 20% 2 44 – 52 52,5 48 6 20% 3 53 – 61 61,5 57 9 30% 4 62 – 70 64 70,5 66 7 23,33% 5 71 – 79 79,5 75 1 3,33% 6 80 – 88 88,5 84 1 3,33% Total 30 100% Picture. 1 Histogram of Conventional Group Experiment Group Learning Results (Students with Duolingo Android Application Methods) From the answers of 30 students who are sampled in the group using the Duolingo Android Application, the lowest value was 37 and the highest 83. To compile the data in the frequency distribution table, the Sturges’ rule was used to obtain the number of classes, class ranges, and class lengths: Table. 3 Result of Experiment Group No X2 (X2) 2 No X2 (X2) 2 1 70 4900 16 70 4900 2 80 6400 17 60 3600 3 70 4900 18 50 2500 4 95 9025 19 55 3025 5 80 6400 20 50 2500 6 75 5625 21 90 8100 7 70 4900 22 80 6400 8 70 4900 23 80 6400 9 75 5625 24 80 6400 10 90 8100 25 85 7225 11 65 4225 26 60 3600 12 70 4900 27 75 5625 13 85 7225 28 70 4900 14 80 6400 29 70 4900 6 6 9 7 1 1 0 2 4 6 8 10 35-43 44-52 53-61 62-70 71-79 80-88 Series 1 Column1 Column2 Student’s Vocabulary Mastery 178 | IJET| Volume. 7, Issue 2. December 2018 15 80 6400 30 70 4900 Total 2200 164900 Table. 4 Frequency Distribution of Experiment Group No Class Interval Absolute limit Mid- Point Absolute Freq Relative Freq 1 50 – 57 57,5 53,5 3 10% 2 58 – 65 65 65,5 61,5 3 10% 3 66 – 73 73,5 69,5 9 30% 4 74 – 81 81,5 77,5 10 33.33% 5 82 – 89 89,5 85,5 2 6,67% 6 90 – 97 97,5 93,5 3 10% Total 30 100% Picture 4.2. Histogram of Experiment Group Testing Data Analysis Requirements Normality test Normality test is carried out on student value data using the Duolingo Android Application method and students with conventional methods are carried out using the Lilliefors test. This is to find out whether the sample group comes from a population with normal distribution or not so that the sample group is quite representative of the research. The normality testing for sample groups is as follows. Control Group Lilliefors Test (Students with Conventional Methods) Hypothesis H0: The population is normally distributed H1: Populations are abnormally distributed Data analysis Based on the value of the test results regarding students with the conventional method, Lilliefors test analysis tables are arranged to determine L0 which contains Zi, F (Zi) and S (Zi) as shown in the table. Table. 5 Normality Test of Conventional Group 3 3 9 10 2 3 0 2 4 6 8 10 12 50-57 58-65 66-73 74-81 82-89 90-97 Series 1 Column1 Column2 Kusumadewi and Widyastuti 179 | IJET| Volume. 7, Issue 2. December 2018 Because the value of L0 = 0.104 and L table = L0.05 (30) = 0.161 which indicates that L0 L table Table. 6 Normality Test of Experiment Group Because the value of L0 = 0.115 and L table = L0.05 (30) = 0.161 which indicates that L0 t table, this means reject H0, accept H1, so that conclusions can be drawn, the results of student learning English with media Duolingo's Android Application has a positive effect compared to conventional student approaches. DISCUSSIONS Mastery of English vocabulary is very essential to have to face the current era of globalization. There is a lot of media that can be done to improve students' vocabulary learning outcomes, one of them is the Duolingo Android Application media. Use of media The Duolingo Android application is expected to motivate and facilitate students in learning activities. Based on the test above, it turns out that there are differences between the learning outcomes with conventional methods with the results of learning using the Duolingo Application method on the mastery of English vocabulary mastery in grade VIII students of Omega Science Institute Junior High School Tutoring. Student test results after getting media vocabulary learning The Duolingo Android application is far better than the results of student tests using conventional learning media. Comparison of the results of tests of vocabulary mastery skills with media Duolingo Android applications and with conventional learning media are as follows. Table 10. Summary Table of the Research Result Score Result of Conventional Group Result of Experiment Group Mean 56,33 73,33 Median 55,5 73,5 Mode 57,9 74,39 Standard Deviation 12,24 11,09 Variance 149,89 122,99 The table above shows a summary of the statistics of the mean, median, mode, standard deviation, variance in the results of conventional learning methods and learning methods of the Duolingo Android Application on mastery of English vocabulary. The values of the conventional method are seen to be under the values of the Duolingo Android Application method. Based on the results of the above calculation, the t-test score is 5.64 where n = 30 with df = nA + nB-2 = 58, then t- table 1.70 and it turns out t-test 5.64> t-FRtable 1.70 thus Ho is rejected. This means that the H1 hypothesis is accepted, there is an influence of the use of the Duolingo Kusumadewi and Widyastuti 185 | IJET| Volume. 7, Issue 2. December 2018 Android Application on English vocabulary abilities of class VIII students of Omega Science Institute Tutoring. From the calculation results obtained that Ho is rejected or the test results are significant which means mastery of English vocabulary of students who use Duolingo application media in the experimental class is higher than the conventional class which is only fixated on the textbook or lecture method. This shows that there is a significant influence on the mastery of English vocabulary between students taught using Duolingo android application media with different conventional teaching. The difference is shown that treatment is different in the English teaching strategy in the class. In the experimental class, using the Duolingo android application media as an instrument for mastering the vocabulary of students in the class, while in the control class, the author uses the book as an instrument for mastering students' vocabulary. After that the test was given in the form of work search word play to both the experimental and control classes. CONCLUSIONS Based on the results of the study obtained the value of the control group (students with conventional methods) the number of respondents 30 students, with the lowest value of 35 and the highest value 85 then obtained an average value (mean) of 56.33 Whereas the results of the study of experimental groups (students with methods Duolingo Android application) with the same number of respondents, 30 students obtained the lowest value of 37 and the highest score of 83, the average value of 73.33 was obtained. Then based on data from hypothesis testing, the t-test result is 5.64 where n = 30 with df = nA + nB-2 = 58, then ttable 1.70 and it turns out ttest 5.64> ttable 1.70 thus Ho is rejected. This means that the H1 hypothesis is accepted, there is an influence of the use of the Duolingo Android Application on English vocabulary abilities of class VIII students of Omega Science Institute Tutoring. Based on the testing of the hypothesis above it can be concluded that students who use Duolingo application media in the experimental class is higher than the conventional class which is only fixated on the textbook or lecture method. This shows that there is a significant influence on the mastery of English vocabulary between students taught using Duolingo android application media. Acknowledgements This research was partially supported by DIPA Indrapratsa PGRI University. We thank our colleagues from Indraprasta PGRI University and OMEGA Sains Institute who provided insight and expertise that greatly assisted the research, although they may not agree with all of the interpretations/conclusions of this paper. We thank our friends for sharing their pearls of wisdom with us during the course of this research and also who give comments that greatly improved the manuscript. We would also like to show our gratitude to our families who support us to finish this research. Last but not least, we hope that this research will be useful for further research in the same area. Student’s Vocabulary Mastery 186 | IJET| Volume. 7, Issue 2. December 2018 REFERENCES Definisi: penguasaan, Arti Kata: penguasaan. (n.d.). Retrieved December 19, 2018, from http://www.artikata.com/arti-369095-penguasaan.html Definisi penguasaan - Kamus Bahasa Indonesia. (n.d.). Retrieved December 19, 2018, from http://kamusbahasaindonesia.org/penguasaan Dudeney, G., & Hockly, N. (2007). How to teach English with technology (2. impr). Harlow: Longman, Pearson Education. Flowerdew, J., & Miller, L. (2005). Second language listening: theory and practice. Cambridge ; New York: Cambridge University Press. Hamalik, O. (1995). 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