语伴and语言伙伴是一样的。 语伴is a shortened from of 语言伙伴, there is no difference. for native speakers, we prefer the first one 语伴. partner is 伙伴，instead of 交换，语言交换是指language exchange.

Do NOT translate literally. When running into translation difficulties, it's better to rephrase it into something else. e.g. I want to find a language partner - I want to find someone to practice Chinese with. Instead of the former, which you're unsure of, you can translate the latter: 我想找个朋友（or 伙伴/人）练习中文。 A lot easier than sticking to a specific word to translate.

就是语言伙伴!语伴听起来有点奇怪，不够直接。

语言伙伴 = yǔ-yán huǒ-bàn

语言伙伴