## 2 Mobile Learning in English as a Second Language Education  
Mobile learning has become a tool used to capture the attention and motivate students. This section aims to define the characteristics that mobile technology brings to an innovative educational model for learning English as a second language. In addition, it is intended to define the teaching models of this language, with the objective of identifying which of them, working in conjunction with a mobile application, can be used to generate a hybrid model of English language teaching. To define mobile learning, it is important to consider the concepts of different authors, so that the information obtained will be much more complete and enriching. According to [PERSON], mobile learning is a learning process that uses and relies on mobile technologies [14]. [PERSON] defines mobile learning as a process of knowledge acquisition through the interaction of participants from different contexts who are related to each other using digital technology such as cell phones, smartphones, pads, pods, etc. [15]. Other authors consider mobile learning as the study of how the mobility of learners, augmented by personal and public technology, can contribute to the process of acquiring knowledge, skills and experience, etc. [16]. From the perspective of [PERSON] and [PERSON], the most important characteristics of mobile learning can be listed as follows [17]:  
* **Portability**: The acquisition of knowledge can be moved to any place and time, facilitating the student's learning regardless of where he/she is. * **Availability**: Access to all information. * **Personalization**: The information can be adapted to the user's needs and style. * **Social Connectivity:** Collaborative work among the same users of an application. * **Motivation:** It motivates students to get involved in their education. Based on these characteristics, mobile learning transforms traditional education into informal education, where learning is centered on the student, making him or her a constructor of his or her own learning [18]. In the last few years, learning using mobile devices (tablets and smartphones) has been extended to various activities related to education. Today, mobile technology has increased its growth and penetration worldwide. In a report developed by Cisco, it is predicted that cell phones will have an annual growth rate of 2%, which means that by 2023, more than 70% of the world's population will have a mobile device to use [19]. According to [PERSON], teachers today have opted for the use of mobile applications to motivate students toward self-learning [20]. After choosing mobile applications according to the needs and purposes of the teacher and students, the process of self-learning is developed on each student's device in only a few minutes a day; teachers can develop in their students the meaningful construction of new knowledge. [PERSON] explains in his article how the creation of fascinating mobile applications has sparked interest, motivation, and curiosity in learners [21]. This has allowed mobile apps to become a reliable and useful tool when learning second languages such as English. [PERSON] presents in his work the advantages of using mobile applications in the process of L2 teaching [22]. Among the applications available, many are friendly and innovative, and most are free and easily accessible to young audiences. The advantages that mobile applications offer learners are endless and very useful for the process of acquiring a new language, given the current age of the pandemic and hybrid teaching in the classroom setting. [PERSON] lists some of them [23]:  
* The apps consider the four core English language skills: reading, speaking, listening, and writing. * Learners can access their apps anytime, anywhere. * Learners can interact through the apps with their peers or with other people around the world. * The apps are free of charge. * They can reinforce knowledge and provide tips to perform better in different skills.