Apparently there's some in game voice chat testing going on.
Personally, I don't think adding in an in game voice chat (jeez, that's a weird sentence) is a good direction for league. Now I'll admit, I haven't been playing league for the longest time (I started playing whenever the heck bard came out for reference.) but still, I don't think voice chat will help league evolve any further.
My Concern: Let's address the elephant in the room, league is known for having a pretty, uncivil, community. And with that in mind one of the only things that's kept this game from reaching unbearable levels of toxicity is the ban system, criticize it all you want its there and it works. Why? because its "easy" to monitor, its easy for a computer program or whatever to monitor the players in game behavior through what they build, what they say in chat, etc. The problem arises when voice chat is thrown in. Voice chat is extremely hard to place bannable restrictions on because I don't think there's a computer program in Riot's arsenal that can analyse speech and seek out the insulting/racist/homophobic speech out there. Unless they hire a LARGE staff of real human beings to monitor all chat logs for all games and ban people accordingly (which sounds like one of those "loose faith in humanity" type jobs.) then I don't think this system will be very good at banning those people Riot doesn't want to see in their community.
The Counter-Argument: Now its not like their adding in the voice chat just because all the cool kids on the block have it now. There is at least some reason to have it, and that reason is teamwork. It's hard to talk, or type, strategy to people while in the midst of farming or a team fight, and pings aren't that effective, though they help. As stated in the article the reason they would have a voice chat is to help people literally talk strategy.
The Solution: Here is my humble solution to this problem. Make an in-client third party chat system! (Que trumpets) What I picture is an option on the client where you can invite players on your friends list to a voice chat party (think xbox live or skype). This way the chat system can be used by people you trust and this system isn't forced on anyone who's shy like me and dosn't want to talk to a bunch of randos (sorry randos, i'm sure your all wonderful people).
TL:DR? If Riot wants to implement a in-game voice chat system, then I think they should make it like xbox live and skype (where you can invite people you want). And not force it on anyone else.