Wireless communication technology are applied to many fields such as GPS navigation, wireless monitoring system as well as learning various materials including learning language skills. Mobile learning can take place either within the classroom or outside it. In the former case, mobile phones possessing appropriate software are very effective in collaborative learning among small groups. Although this type of learning has nothing to do with the mobility property of such devices, it provides the learners with the opportunity of close interaction, conversation, and decision-making among the members of their group due to the specific design of the learning activity on mobile phones. These types of interaction among learners and their physical movement can hardly be achieved when desktop or laptop computers are to be used.
Mobile learning technology is more useful for doing activities outside the classroom. Such activities enable learning to be more directly connected with the real world experiments. Moreover, learning through mobile phones outside the classroom has the advantage of better exploiting the learner's free time; even the students on the move can improve their learning skills .
SMS-based learning is another development in the use of wireless technologies in education in which receiving wanted text messages supports learning outside of classroom and helps learners benefit from their teacher's experimentation with mobile technology .
Game-based learning is another theme for mobile learning in which learning materials are so designed to be integrated with aspects of physical environment. In such environments, learning activities are facilitated using the mobile technology which serves as a link between the real world of knowledge and the visual world of the game. TimeLab, for instance, is a game about climate change and its effects. Players succeed to get information about the introduction of possible new environmental laws via their mobile devices in different locations as they progress in the game. They will later discuss the results of the game in the classroom .
The m-learning games can also be used to teach second language skills such as vocabulary, pronunciation, grammar, listening and reading comprehension and spelling. According to
Canny, cell phones offer an ideal platform for learning since they are ubiquitous, affordable, compact and wireless .
The researchers of the project MILLEE at the university of California (UC Berkeley) concentrated on simple English language skills and designated a series of games that constitute a curriculum equivalent to an ESL course. They tested their cell phone-based learning games in North India. They reported that the game play can produce significant learning benefits, and this type of learning will enhance student's basic skills and provides clues to the sustainability and scalability of their approach Microsoft research program).
Many researchers were so interested in MALL approaches that they attempt to provide some strong supports to conduct further studies on this discipline. Today, mobile learning is easily possible by delivery of various learning materials or content to learners through the mobile devices. Various activities related to language learning are supported by mobile devices among which we can name SMS, internet access, camera, audio/video recording, and video messaging (MMS).
One of the advantages of mobile learning is that collaborative learning is very encourages in this kind of learning. That is, different learners are able exchange their knowledge, skills and attitudes through interaction. Collaborative learning helps the learners to support, motivate and evaluate each other to achieve substantial amounts of learning, the property which is almost absent in other kinds of learning. One can attain a good collaborative approach simply by using a mobile device as an environment for learning, which is, of course, highly dependent of the users than the devices. Devices, in fact, act as pencils and calculators which are the basic equipment in a learning process of a student. What is important, here, is the communication between the learners, as an important factor in language learning is the interaction in the target language 
There are different mobile devices in the market compatible to the needs of different users. The basic activities can be performed by many mobile phones. However, for language learning, the cost and technologies related to the mobile devices should be taken into consideration. Such learners can use their customized mobile devices for language learning based on their own abilities. The possible MALL activities and users for some mobile devices has been shown in Appendix 2 
Mobile Assisted Language Learning
When, in 1973, the mobile devices were invented for the first time, no one ever thought some day they would become an important part of routine life. As soon as the mobile phones became a crucial part of our lives, there felt a need for using them in language learning tasks.
These days mobile devices such as PDAs, phones, and other handheld devices, are used everywhere for doing everything ranging from voice calling to making short message, video chat, listening to audio (Mp3, Mp4, Mpeg), web surfing, shopping, and the like. Apart from these benefits, mobile devices have increasingly grown toward becoming tools for education and language learning, and all its users from teachers or students are getting used to this
environment to make education as ubiquitous as possible. Moreover, the emerging of internet made open and distance learning a means of receiving education from all parts of the world. In a short period, the attractiveness of distance learning led to the realization that various mobile devices provide a very effective resource for education. This way, many researchers tried to make mobile devices a rich resource for teaching and learning. It was, in fact, a challenging affair to cover learning tasks by a mobile phone .
MALL deals with the use of mobile technology in language learning. Students do not always have to study a second language in a classroom. They may have the opportunity to learn it using mobile devices when they desire and where they are. As learning English is considered a main factor for professional success and a criterion for being educated in many communities, providing more convenient environment for people to learn English is one of the strategic educational goals towards improving the students' achievement and supporting differentiation of learning needs.
The advances in technology and wireless networking expanded the potentiality of mobile phones to be utilized in educational environments. In fact, they suggest communicative language practice, access to authentic content, and task completion but they are not in and of themselves instructors (Chinney, 2006). These attributes are best fitted for language teaching and learning. For instance, mobile phones can be used to send educational materials and contents to learners via Short Message Services (SMS). On the other hand, some researchers (Colpaert, 2004; Beatty, 2003) contend that emphasis should be on learners since employing such a novel and unproven technology is a waste of time and money. However, these devices have generated a branch of studies that relates to language learning and mobile technologies named Mobile Assisted Language Learning (MALL). Kukulska-Hulme and Shield (2008) noted that MALL differs from computer assisted language learning in its use of personal, portable devices that enable new ways of learning, emphasizing continuity or spontaneity of access and interaction across different contexts of use. They separated studies about MALL into content-based (development of activity type and learning materials, the formal context of M-Learning) and design related models (development of leaning and materials and activities for mobile devices, the informal nature of M-Learning). Studies dealing with design issues seem to differ from the context based models in that they less emphasize on traditional educational paradigm that students are provided with materials by the teacher rather than allowing learners define their own learning and even provide materials to other learners. A review in studies related to MALL shows most of them have used SMS for learning vocabularies, taking quizzes and doing surveys. Stanford Learning Lab developed Spanish study programs utilizing both voice and email withmobile phones in which vocabulary practice, quizzes, word and phrase translations, and access tolive talking tutors toke place. Small chunks quiz delivery was reported to be effective and therewere great potential of automated voice vocabulary lessons and quizzes. Small screen sizes wereacclaimed to be unsuitable for learning new content but effective for review and practice (Chinnery, 2006). In addition, the activity relating to automated voice was abandoned, primarily because of problems with voice recognition software (Kukulska-Hulme and Shield, 2008). Thornton and Houser (2002; 2003; 2005) used mobile phones to provide vocabulary instructionby SMS at a Japanese university. Short mini-lessons were emailed to students three times a day.The students learned via SMS were twice more successful in the number of vocabulary words and their scores comparison to students who had received their lessons on paper. Great motivation was reported and students wished these kinds of instructions continue.
There are many researches and developments towards the use of wireless technology for different aspects of language learning. In the following lines it has been tried to demonstrate the benefits of using mobile phones in learning English as a second language. Areas of mobile-based language learning are diverse among which the most common ones are vocabulary, listening, grammar, phonetics, reading comprehension, etc.