Nowadays English has been learning all over the world. Enthusiastic teachers know how and from what age to start teaching language to their learners. So, when will it be better to start teaching foreign language to young children? From the ages of 2–4 or 5–7, may be 8–10. Teachers all around the world have discussed this problem and can not come to the end of their discussion. One say young children of the ages 2–4 may learn foreign language. While others say, how can they learn foreign language? At this age even in their native language they start speaking with difficulty. From the ages of 5–7, they have not writing and reading abilities in foreign language. What if at the ages of 8–10 may be this age is ideal to start learning foreign language. But neuro-physical clinical investigations suggest that the speech learning center of the brain is at its maximum capacity between the first and ninth year of life. But most school experiments have determined that starting a foreign language at the ages of 8–10 on the one hand does not fail to catch ‘the teachable moment’, and on the other gives time for the basic mother tongue skills to have been firmly established. Ideally, a child should not be taught to read and write English before he is literate in his mother tongue. 
The nature of the very young learner does not appear to vary noticeably from nation to nation, and this suggests that the same general psychological and methodological principles hold good for teachers of the youngest children wherever they are. For example the limited span of attention noted by Ginsberg in her 5–6 year learning English in Leningrad is found in all young children. Consequently English lessons must be short, but regular. Twenty to thirty minutes each day is ideal for children between 5 and 7, and a longer daily period, up to forty-five minutes for older primary schoolchildren. Equally, if not more important, it is necessary to switch frequently from one activity to another during the course of lessons: ten minutes is the longest time for which many primary children can sustain an interest in one activity, and for infant and kindergarten learners, the period is even shorter.
Denise E. Murray also agreed with this point of view and he characterized young learners at three stages of development in his book «What English teacher need to know». 
Stage one Preschool (ages 2–4)
This is a sensitive period for language development. Children at this stage are usually quite good imitators of speech sounds. They do not work well in groups and prefer to work alone on something that interests them although they enjoy parallel play (i.e., playing alongside other children but not directly with them). They have very short attention spans and love to repeat the same activity over and over again. They need concrete experiences.
Stage two. Grades K–2 (ages 5–7)
Like preschoolers, they need concrete experiences and love to name objects, define things, and learn about objects in their own world. They learn new concepts best when they are taught in binary opposites. They learn the meaning of largeby referencing it with something in their world that is small. Children at this age also have vivid imaginations and respond well to stories of fantasy. At this age, they learn best through oral language, so they love being told stories with a solid beginning, middle, and end. It is important for teachers to remember that young learners at this age are unskilled in using the small muscles (e.g., the intrinsic muscles) and coordinating fine-tuned motor skills. Reinforcing regular routines helps learners at this age.
Stage three. Grades 3–5 (ages 8–10)
At this stage, children begin to develop characteristics of concrete operations, such as the ability to understand cause and effect. They are also most open at this age to people, situations, and ideas that are different from their own experiences. Introducing children to information about other cultures and countries at this stage is very important. In addition, children at this age can learn how to work with other students, particularly in groups, and they like writing notes to each other and to pen pals, and creating skits and participating in role plays. Like children in younger grades, they continue to benefit from imaginative and creative play, and they also like a story that has a definite beginning, middle, and end. Using rubrics and peer assessments can be used with children at this age.
Adolescents are often the neglected group of language learners in terms of focus and specific teacher preparation in most English language teaching contexts. As a profession, language teachers and researchers have spent much of their efforts on understanding and educating adult academic learners, and, in the past decade, have added young learners to the mix; however, adolescent learners do not fit into either group. They are different from young learners because they have had a more diverse set of experiences, including social and academic experiences; yet, they are not adults because they do not have the breadth and depth of experience nor the cognitive maturity of adults. From about the ages of 10 to 14, learners grow and develop more rapidly than at any other stage in life, except for infancy. In addition, adolescents are often very much aware of their growth and development, and this awareness can make the changes they are experiencing uncomfortable and difficult .
Adults learning English bring to the task a mature personality, many years of educational training, a developed intelligence, a determination to get what they want, fairly clear aims. Malcolm Knowles in his book «The modern practice of adult education» identifies four basic concepts that are central to adult learning .
The first is self concept. Whereas the child is depend on those around him and relies on the instructor to direct the learning, the adult acts autonomously in relation to others. Adults are capable of being self — directed, of being able to identify and articulate what they want to learn in dialogue with the teacher. Teachers guide the learners to their own knowledge rather than supplying them with facts.
The second concept is self — experience. Children as learners are building a knowledge base and must be shown how their life experiences connect with the present learning. This is not always appropriate for the adult learner who brings a wealth of life experience and wisdom into the learning. They need to connect the learning to their knowledge base integrate new information with previous experience. They must recognize the value of learning.
The third concept is the student’s readiness to learn. In traditional pedagogy teacher decides what the students need to learn and curriculum is developed apart from the learner. Learning is compulsory and learners often the no reason for taking a particular course. They just know they have to learn the information. In andragogy the learner takes more active role in deciding what will be taught and when. Adult education is more learner centered. Adults are often able to identify the learning needs that arise from their social situation. Learning is self — initiated and tends to last a long time.
In the last third concept there is a different orientation to learning for adult. Children have been conditioned to have a subject — centered orientation to learning whereas adults tend to have more problem- centered orientation. The difference is one of the time perspective. Children tend to focus attention towards the future whereas adults are concerned with the present. Thus adult learners are interested in learning how to solve the problems that they experiencing in daily lives.
To put it briefly, people should learn and must be taught in all stages of their life to enlarge their experience and beautify their life. As in old proverb says «Live and learn».
1. Jeremy Harmer. How to teach English.
2. Malcolm Knowles. The modern practice of adult education.
3. Denise E. Murray, Mary Ann Christison. What English language teachers need to know. New York 2011.
4. Geoffrey Broughton. Learning English. London.