Cannot find 'weak' in scope iOS swift

i am trying to avoid memory leak using clousures in swift , but swift is not recognising the [weak self] inside the closure.

  //  class :
    
    class LanguageClass {
        
        var languageClosure : (() -> ())?
        var name : String = ""
        
        init() {
            self.languageClosure = { [weak self]
                print("\(self.name) is the language")
            }
        }
        deinit {
            print("deinitialized")
        }
        
    }
    
   // consumption :

      var swiftLanguage : LanguageClass? = LanguageClass()
      swiftLanguage?.name = "Swift"
      swiftLanguage?.languageClosure?()
      swiftLanguage = nil