The summoner and the champion have a telepathic connection that allows them to communicate, so why can't we understand Gnar. I really do just want some lore explanation about this, or have you guys decided that Lore is dead now?
gnar might not have a language since hes suppose to be all "caveman" style he might PRE-DATE language as we would understand it and use grunts and growls to communicate?
This isn't a new phenomenon. Heck, Rammus has basically no Voice-Over lines besides "Okay," and he is much older than Gnar. Seeing as he is the Yordle equivalent of a Caveman, I don't think he should speak in anything more than grunts.
Think of it this way. 
understands language, but can't speak it. Other ancient champions have lived through the ages and have probably learned it from listening to people. Gnar is primordial, and possibly doesn't have the vocal cords necessary to speak.
The Summoner and Champion can communicate, yes, but that doesn't mean that the Summoner is given a Babel Fish which translates Gnar's "language" into a medium the Summoner can understand. Every Champion we've seen speaks the same shared language, even if in a broken manner such as with Kog'Maw, and in-lore there has yet to be a Champion who didn't have the ability to personally speak it themselves (Sona would if she could). Gnar's a primordial furry terror fresh out of an icecube, he hasn't been taught their language, if he's at all capable of learning or speaking it period. The Summoner can talk at Gnar because the Summoner helps influence the Champion's actions even without communications, so Gnar can get the gist of what the Summoner wants him to do, but it's completely plausible to assume that that particular interaction is one-sided.
Uh...duh. Lore has been dead since like...Christ, Zac probably. Summoners, the League, and it's purpose have been quietly bring phased out of the game with visual and lore updates. LoL is going to just be about random fantasy characters fighting for no reason in an imaginary symmetric battlefield, you can pretty much forget about any "lore team" doing anything but collect a paycheck every 2 weeks.
Look at the lore for Gnar. Look at it. He was a caveman who was frozen in ice and now he's unfrozen. That's it. That's all. No character interaction, no VoiceOver, no personality, and he's the only new champ who'll be out for four months. If you think the lore team is doing anything resembling a job when you look at that , you're delusional.
