lots of linguists find that there are many differences between young and adult second language learners ,and now we are going to see the differences between them and how learning styles and teaching a second language differ with young and adult second language learners. First, adults and children learn second language differently: children can learn second language easier than adults because their critical period didn’t pass so they can acquire the language fast and the pronunciation is easy for them and they can learn from hundred to thousands words within a year on the other hand adults already passed their critical period so it’s harder to them to acquire second language and they have to make effort to learn it. Second, they have different motivations: children don’t have certain reason or motivation to learn second language, but adults have specific reason to learn second language, preparing for college or for their jobs. Third, teaching styles differ from young and adult learners: children acquire second language on the same way they acquire their native language by practicing and interaction, they learn by watching videos , movies and listening to songs. On the other hand adults learn the language on courses or classes or travel to study the language abroad by interacting with the native speakers .Finally, proficiency differences: children acquire second language quicker than adults because they are more exposed to the language they spend more hours learning the language on the classrooms and home but adults are less exposed to the language.