I believe that you can learn greeting and basic sentences or questions which you might have during you trip because Japanese pronunciation is not so difficult. However it’s difficult to have a conversation like... to understand the answer from native Japanese (especially with elder people). My friend, he can say only Konnichiwa and Arigatou but he really enjoyed his holiday in Japan. His tips were just he kept his smartphone with keeping Wi-Fi and he used google map and translation. I hope you will have a wonderful trip to Japan!!