DetectKeyboardInput.swift

func supportsKeyboard(lang: String?) -> Bool {
	guard let _lang = lang else {
		return false
	}
	let predicates = [
		Predicate(format: "SELF == %@", "en"),
		Predicate(format: "SELF like[cd] %@", "en-*")
		]
	for predicate in predicates {
		if NSArray(arrayLiteral: _lang).filtered(using: predicate).count > 0 {
			return true
		}
	}
	return false
}

supportsKeyboard(lang: nil)
supportsKeyboard(lang: "en")
supportsKeyboard(lang: "en-us")
supportsKeyboard(lang: "jp")

////
class ViewController: UIViewController {
	@IBOutlet weak var textField: UITextField!

	override func viewDidLoad() {
		super.viewDidLoad()
		
		// Do any additional setup after loading the view, typically from a nib.
		NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardTypeDidChange(notification:)), name: NSNotification.Name.UITextInputCurrentInputModeDidChange, object: nil)
	}
	func keyboardTypeDidChange(notification: Notification) {
		print(">", notification)
		textField.placeholder = textField.textInputMode?.primaryLanguage
		
		//UITextInputMode.currentInputMode()
		//po UITextInputMode.activeInputModes().forEach({ print($0.primaryLanguage) })
	}
	
	func selectionDidChange(_ textInput: UITextInput?) {
		print(textField.textInputMode?.primaryLanguage, textInput)
	}
}