monitor input events

Hello, I need to monitor input events and convert keycode to symbol. E.g. convert kHIDUsage_KeyboardQ to symbol according to used keyboard layout.

1. Are there any API to get current keyboard layout (language) in C++? If I understand correctly, the API TISGetInputSourceProperty() is deprecated.
2. Are there any way to monitor keyboard layout changed? (some system notification in case of keyboard layout change)
3. Are there any way to translate keycode to symbol except UCKeyTranslate() which is part of deprecated Unicode Utilities?

Thank you in advance.