45.Many signed languages, including American Sign Language, have born within the last few centuries.

⇒Have born → have been born

46.Minority communities for instance aboriginal peoples over 80% whose native languages will die with the current generation, account for most of the world's languages.

⇒Whose→of whose

47.According to linguists,children can learn several languages well,as good as they no when to speak each one

⇒as good as → as well as

48.According to me,I think if one is from the country with strong and old traditions, it will be rather difficult for him to adapt to the new customs and more oneover to reject his own

⇒moreover to reject → moreover, to reject

49.Individuals define themselves by nationality,ethnic,language,clothing and food.

⇒ethnic → ethnicity

50.In forest worshiping,people worship the gods of trees and villagers sacrificed their lives to protect the village

⇒sacrificed → sacrificing

45. have born => have been born

46. whose => of whose

47. as good as => as well as

48. moreover to reject => moreover, to reject

49. ethnic => ethnicity

50. sacrificed => sacrificing