Steve Kaufman of LingQ shares his opinion on traveling to learn a language, and using travel phrasebooks. He's a man that speaks many languages, and yet despite studying a phrase book for Vietnamese, he was only able to use a few words during his trip.
On his trip, he spent some time in South Korea. He has studied Korean extensively. In this video he also mentions that studying for six or more months was needed before he could have any meaningful communication. He mentioned that despite his past studies, it took a few days before he got into the swing of speaking the language.