Enum with Nested Struct

enum PersonDescription {
    case Singular, Dual, Plural
    
    struct Portrayal {
        var literal: String, numeral: Int
    }
    
    var portrayal: Portrayal {
        switch self {
        case .Singular:
            return Portrayal(literal: "Singular", numeral: 1)
        case .Dual:
            return Portrayal(literal: "Dual", numeral: 2)
        default:
            return Portrayal(literal: "Plural", numeral: 3)
        }
    }
    
    var allPersonNumbers: [PersonDescription] {
        return [.Singular,.Dual,.Plural]
    }
}

func fillNounFields(allDeclensions: [String: AnyObject]) {
        func populateFields(declinedForms: [String: AnyObject], number: PersonDescription) {
            for wordCase in WordCase.allCases {
                var textFieldName = number.description.literal.lowercaseString + wordCase.rawValue.capitalizedString
                var textField = self.valueForKey(textFieldName) as? NSTextField
                if let textFieldToFill = textField {
                    if let declinedForm = declinedForms[wordCase.rawValue.lowercaseString] as? String {
                        textFieldToFill.stringValue = declinedForm
                    }
                }
            }
        }
        
        for (number,declinedForms) in allDeclensions {
            if let declinedNounForms = declinedForms as? [String: AnyObject] {
                var person: PersonDescription = { () -> PersonDescription in
                    var person: PersonDescription = PersonDescription.Singular
                    
                    switch number {
                    case PersonDescription.Singular.description.literal:
                        person = PersonDescription.Singular
                    case PersonDescription.Dual.description.literal:
                        person = PersonDescription.Dual
                    case PersonDescription.Plural.description.literal:
                        person = PersonDescription.Plural
                    default:
                        NSLog("default: \(number)")
                    }
                    return person
                }()
                populateFields(declinedNounForms, person)
            }
        }
    }