Investigating the Effectiveness of the Duolingo Platform in Developing Learners’ Vocabulary and Grammar Acquisition Case of CEIL Adult Beginner EFL Learners

Med. Lamine Debaghine Setif 2 University
Mohamed Lamine Debaghine, Sétif 2 University


This study intends to investigate the effectiveness of Duolingo, a free online language learning platform, the objective of which is to develop English vocabulary and grammar acquisition for adult beginner. Adult learners of English tend to have busy schedules and find it hard to practise and accomplish their assignments outside the classroom. To see to what extent the Duolingo is effective, seventy adult learners of English enrolled in the intensive school of foreign language teaching were selected for the study to test the hypothesis that adults using the Duolingo show better results than who using the teacher-directed methods. After a placement test, the participants were equally divided into two groups: a control group and a treatment group. The treatment group was requested to complete at least 5 Duolingo lessons, lasting between 15 to 20 minutes every week. The comparison of the results collected on the basis of the pre and post tests were used to show the degree to which informants managed to improve their vocabulary and grammar. The results collected after a period of observation which lasted 10 weeks for both groups revealed that the improvement of the treatment group was statistically significant. The improvement corroborated the effectiveness of the Duolingo platform in developing learners’ vocabulary and grammar acquisition.

Keywords: Duolingo, Blended learning, ICTs, Improvement of language abilities, Online language learning, Vocabulary and grammar.

  1. Introduction

The fast growth of technologies has benefitted education in more than one way, and led to the emergence of what is nowadays known as “Educational Technologies” that Rhonda Robinson et al ( 2008:15) define as “the study and ethical practice of facilitating learning and improving performance by creating, using, and managing appropriate technological processes and resources.” E-learning is a term used to describe this type of learning that is based on the use of the web and other Internet technologies. It is also referred to as the intentional use of networked Information and Communication Technology (ICT) in learning and teaching (Naidu, 2006). The learning process takes place through the use of technology in order to process and assess knowledge and information (Alwi, et al., 2010). Nowadays, there are many types of e-learning among which Computer-based learning (CBL), Web-based learning (WBL), Computer Assisted Language Learning (CALL).

As regards Miles, S., & Kwon, C. J. (2008) “CALL is increasingly seen as an attractive option for learning”. In other words the applications of CALL for vocabulary learning will cover the amount of vocabulary that learners need in order to acquire the language and substitute the limited time while learning inside the classroom.

Lately, a new generation of CALL has appeared known as mobile assisted language learning (MALL) using cell phones and handheld devices which have entered the language curriculum due to easiness and accessibility (Abdous, et al. 2009).

Duolingo is a free online language-learning tool available on different platforms (Website, Android/iOS phones, and tablets). It offers 23 different language courses using 23 languages. The tool is available on iOS, Android and Windows 8 and 10 platforms with about 150 million users worldwide. Duolingo provides courses in the four skills .

Duolingo has some advantages compared to traditional teaching for it motivates participants to learn autonomously. Furthermore, it inspires users to review what they have already learnt and remember what they have forgotten (Gilson, Wells, & Tatro, 2012). Jordão (2009) argues that teacher must support their learners to use creativity and new technologies in their classrooms.

Vesselinov & Grego (2012), conducted a study to investigate the effectiveness of Duolingo and concluded that the majority of the participants showed positive attitudes towards using Duolingo. They liked the product as it helps enhancing their language . Vesselinov’s and Grego’s findings showed that the complete beginners would take an average of 26 to 49 hours of study with Duolingo to cover the material for the first college language semester. On the other hand, Krashen (2014) commented that the findings of this study are arguable; especially the fact that the investigators did not take into consideration the number of participants who did not finish the study. However, for Krashen Duolingo does not procure genuine language competence because it is “like most foreign language instruction based on conscious learning”.

In another study aiming at exploring the effects of using Duolingo in the English learning process, de Castro, et al. (2016) stated that with the use of Duolingo provides huge significance in terms of effectiveness and confidence when communicating in English . The use of this application provided a great deal of freedom related to the language practice schedule. They also found that Duolingo helped a lot in the early stages and proved to be a very effective tool in improving pronunciation as well.

Alongside, Finardi, et al (2016) conducted a study aiming at analysing the limitations of the Duolingo platform. They concluded that the Duolingo fosters vocabulary and grammar development. Nevertheless, due to the absence of interaction and contextualised language production, this application fails in developing language in general sense. The participants claimed as well that the presence of the teacher is still relevant to foster interaction and guide them during the learning process.

  1. Conceptual Basis

In the present investigation the researcher opted for a hybrid experimental design in order to benefit from the flexibility and adaptability gained from the combination of different conventional designs. This study relied on random drafting to assign participants either to T group or C group. This research is also a single-site case study based on Adult students inscribed for a General English language course for the academic year 2016/2017 and their teachers in the CEIL, at Mohamed Lamine Debaghine Sétif2 University.

    1. Research Questions

The current probe sought to answer the following research questions:

  1. Is there a significant difference between the pre-tests and post-tests of the students’ vocabulary and grammar learning achievement?

  2. What are the students’ opinion about the Duolingo learning application and its value for the learning of vocabulary and grammar?

    1. Research Hypotheses

In accordance with the previous research questions, the following hypotheses were generated:

      1. Null hypothesis.

There is no significant difference in the average mean score on the vocabulary and grammar achievement test between learners who will be taught by using the Duolingo platform (T group) and those who will be taught without the Duolingo platform (C group) in the Post-Test.

      1. Alternative hypothesis.

There is a statistically significant difference in the average mean score on the vocabulary and grammar achievement test between learners who will be taught by using the Duolingo platform (T group) and those who will be taught without the Duolingo platform (C group) in the Post-Test.

    1. Methods

In this study, a mixed-method design was followed, relying on both quantitative and qualitative tools in data collection with a dominance of quantitative tools. The probe comported three main phases, having as a core for the study the experimental phase; nonetheless, it was preceded and followed respectively by pre and post-experimental phases. The pre-experimental phase included mainly exploration tools used to gather more information about the problem and the population. Then, the experimental phase which is the cardinal part of this study was mainly composed of a pre-test, a progress test, and a post-test ending with a post-experimental phase of which the aim was to receive an insight about the participants’ attitudes about Duolingo.

    1. Design

The researcher aimed to test the learners on the vocabulary that can be learnt through the English course of Duolingo. Initially, the beginner skills consisted of 247 words including both content and function words. However, the researcher maintained only content words as function words are generally difficult to be tested out of context, for beginner learners. Accordingly, the researcher limited the vocabulary list used in the experiment to 120 items comprising only content words namely: Nouns, Verbs, and Adjectives (See Appendix C). The selected words were taken from the list of words available in the 9 initial units of the Duolingo course. The three testing phases were based on these 120 words. Concerning grammar, the tests included a section that tested the participants as regards the present tense, the use of articles and the plural/ singular forms.

    1. Sample

For the current study two groups were selected. 70 Beginner from the CEIL at Mohamed Lamine Debaghine Setif 2 University This choice is not accidental for the CEIL is generally coveted by adult learners who tend to have busy schedules and difficulties in finding the time and the opportunity to practise English outside the classroom.

      1. Profile of the selected sample.

Tables 2.1, 2.2, and 2.3 show the distribution of the participants between T and C groups in terms of gender, age and occupation.


  1. Data Analysis

Figure 3.1 below shows the progress made by C group between the pre-test (week 0) and the post-test (week 10. It is noticeable that the scores of C group improved in the post-test compared to pre-test. Alongside, Figure 3.2 illustrates the improvement made by T group through the over the course of the experiment i.e. in the pre-test (week 0), the progress test (week 3), and then the post-test (week 10). Here as well, the progress made by T group is quite apparent both in the results of the progress test or those of the post test. However, if both figures are compared to each other, a flagrant difference can be perceived in the achievement of both groups.

    1. Comparison of the Pre-Test, Progress-Test, and Post-Test

Figure 1: Comparison between pre-test, progress test, post-test of T group

Figure 2: Comparison between pre-test, progress test, post-test of T group

    1. Analysis of the satisfaction scale.

Figure 3.3 Satisfaction scale

As shown in table 3.1 and figure 3.3 above, the first question was about knowing whether they find Duolingo easy or not. The answers were as follows: 10 strongly agreed, 13 agreed, 4 neither agreed nor agreed, 3 disagreed and 1 strongly disagreed. The second question was about investigating the facilities Duolingo hoffers in studying vocabulary and grammar. Their responses were as follows: 10 strongly agreed, 15 agreed, 2 neither Disagreed nor Agreed, 4 Disagreed and none of them strongly disagreed. The third question explored whether they enjoyed learning English vocabulary and grammar with Duolingo. 13 Strongly Agreed, 8 agreed, 6 neither disagreed nor Agreed, 3 Agreed and one strongly disagreed. The last question aimed at investigating whether they were satisfied with Duolingo. The answers were 8 Strongly Agreed, 15 Agreed, 4 neither Disagreed nor Agreed, 3 Disagreed and none of them strongly disagreed.

  1. Results

The analysis of the results of the post-test demonstrated that there was less than 0,001% probability that the computed difference between the scores of the post-test of T group and C group was due to chance. These findings help the researcher either reject or confirm the hypotheses that were previously generated. Accordingly, the null hypothesis H0 is rejected since p > 0.05 while the alternative hypothesis H1 is confirmed because p < 0.05. Thus, it can be established that there is a statistically significant difference between the average mean score on the vocabulary and grammar achievement test between T group and C group.

“H0=There is no significant difference in the mean score on the vocabulary and grammar achievement test between learners who will be taught by using the Duolingo platform (T group) and those who will be taught without the Duolingo platform (C group) in the Post-Test.” REJECTED

“H1=There is a statistically significant difference in the average mean score on the vocabulary and grammar achievement test between learners who will be taught by using the Duolingo platform (T group) and those who will be taught without the Duolingo platform (C group) in the Post-Test.” CONFIRMED

These findings validate the results found by Vesselinov & Grego (2012) in the study they conducted to investigate the effectiveness of Duolingo for Spanish Language learners. In their study they established that 30 hours of use on Duolingo is almost the equivalent of the first semester of a language at the university. De Castro, et al. (2016) also found similar results when they investigated the benefits of Duolingo when used as homework with EFL learners. They noticed a significant improvement in students’ effectiveness and confidence in themselves when communicating in English. The use of this application proved to provide a great deal of freedom related to the language practice schedule in manner that learners are able to use the application wherever and whenever they want. Similarly, the findings of Finardi, et al (2016) go hand in with what have been established in their current study. They were able to prove that Duolingo fosters vocabulary and grammar development.

Alongside, the analyses of the satisfaction scale survey revealed that the great majority of the participants (68%-80%) demonstrated positive attitudes in all four questions of the survey. It is to be noted however, that those who showed negative reactions in the survey didn’t exceed (12%) in all questions. That is, the rest of the participants were neutral in their answers. This helps in answering the second research question by saying that the majority of the students reacted positively to Duolingo and appreciated its aid in the learning of vocabulary and grammar. Few students showed negative reactions. The rest were neutral.

  1. Discussion

    1. Pedagogical implications.

This experimental research study has positive change implications for the field of adult education and may have an indirect impact on the acquisition of vocabulary and grammar from different cultural backgrounds. To that end, this research study offers evidence that the integration of the Duolingo learning platform can be significantly helpful in developing students’ general English Vocabulary and grammar. Similarly, the results from this study have impacts on multiple levels, namely: learners, teachers, and educational administrations.

      1. Implications for learners

Learners who engage in educational activities relying on the Duolingo application would help them increase their vocabulary and may help them to assert their confidence within a relaxed learning environment anywhere and whenever they feel the need to. As a result, their level of confidence could enhance their motivation. Addressing the need to acquire the necessary vocabulary of the studied course, adult beginner students will learn and practice the vocabulary and grammar in a genuine and most relaxed manner possible. Consequently, this study promotes the implementation of an online free educational platform that engages both learners and teachers to promote vocabulary and grammar learning regardless of age, time and qualifications.

      1. Implications for teachers.

The learning activities that the Duolingo application relies on can help to produce positive changes in the way new vocabulary is to be taught and learnt. Furthermore, integrating Duolingo as a teaching method might help teachers facilitate an increase in the level of confidence of learners when learning new vocabulary items outside as well as inside the classroom at their own pace and level.

      1. Implications for CEIL and university officials.

The outcomes from this investigation should propel the CEIL and university officials to contemplate seriously about the practicability of the integration of the Duolingo language learning platform as a subordinate tool that might be integrated in the teaching philosophy of the institution. A further investigation is deemed necessary to analyse the cost-benefit ratio of this learning and teaching application on both teachers and any prospective students. Such avenues could include persuading teachers and potential learners inscribed in the CEIL to incorporate the Duolingo online free learning application in their teaching and learning practices. The recommendations deemed least valuable in the findings of this study should be revisited by policy makers and higher education planners.

    1. Recommendations.

From the study findings, the following set of recommendations has emerged:

First, the results obtained in the current study have provided useful insights not only for the evaluation of the effectiveness of the Duolingo online free learning platform as a means to develop CEIL adult beginner learners of English vocabulary and grammar acquisition but also the possibility to administer the Duolingo learning platform to develop other related skills namely pronunciation and grammar. Consequently, it is recommended that oral expression and grammar teachers urge their students to use Duolingo.

Second, Because of Duolingo’s gamification aspects, it is recommended that content teachers use the application as a more motivating alternative for homework and regular book assignments.

Third, Duolingo’s learning environment offers the advantages that learning new vocabulary items with images, sounds and translations is less stimulating and more constructive. Consequently, it is suggested that teachers implement the Duolingo as a nifty stratagem that links content words to images and vice-versa.

Fourth, as Duolingo promotes self-directed learning beyond the course’s requirements, teachers might gauge as well monitor their students’ progress and devise more targeted activities and practice tasks as to validate or review any vocabulary items or structures that are still pretentious to their learners.

Last, The Duolingo application can be used as an after course tool to maintain students acquired level and help them keep practicing the language wherever and whenever they feel the need to.

    1. Suggestions for further research.

This examination might serve as a premise from which the findings could be utilised to stem future research intrigue. In such manner, future research ought to address the impediments called attention to when directing this study. An extensive larger size to speak to a more noteworthy differing qualities of CEIL adult beginner learners of English and their teachers could be utilised as a part of future research plausibility using a more progressed quantitative approach. Notwithstanding, in-depth semi-structured interviews and classroom observations ought to be embraced as strategies to further reviews identified with this theme.

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