Well, believe it or not but researchers of many found that animals do have a form of communication as well as perhaps even a speech pattern that humans may not understand or might ever be able too. So talking between the lions is maybe possible but we won't know cause well, we're not lions. However I do think that there is a bit of sense by what you mean as realistic and non realistic, for example, a Hyena and a Lion, never get along. In fact, saying they do or they can be friends is a bit....Well....I won't even go there. If we were to have super realistic roleplays anyways, what happens if one lion is trying to hint at something, like maybe to go hunting, and than the other doesn't understand it, or is unable to. Not to mention we're still learning how animals show their languages through simple body structure so it doesn't make it any easier when even specialist don't fully understand all their sign language let alone body movements for speech. So, although its probably not the best thing in the world for you, its still needed just to get certain points across.