First off, I don't think that one can actually have much of a conversation, given the limited set of words and phrases, let alone grammar.
Second, it shouldn't be overdone, as usual. Sure it's nice to drop a few phrases here and there, or to sprinkle some words into the conversation. However, the question that one must ask oneself is: "would my character
actually do that?". The reason is simple: when you are brought up with two languages (one "local" one "universal"), and you talk to someone who isn't from your "local" group, would you not
avoid using words and phrases from your local language, as much as possible, in order to reduce chances of misunderstandings and out of courtesy?
The way I see the NPCs in Ojaveda, for example, is that some words of the Enki tongue have migrated into their
local dialect of Yliakums common tongue. I don't think they're merely unable to speak the common tongue properly (if this were the case, they'd have trouble with more complex phrases, not with the common ones like "tabei"!).
Even if it were different, it would not be good to de-facto require any player to learn an additional language simply to be able to play a specific race. If nothing else, it would more or less force players who have comparatively little time to play only the races with no own language, which we clearly cannot allow to happen.
Additionally, the use of full phrases in /say, especially if prolonged, may create the impression that foreign languages are allowed to be used in /say. A new player will be unable to see any difference between the Enkidukai language and any one of the many RL languages the player doesn't speak, quite possibly resulting in the formation of RL langauge groups. This will in turn add to the confusion.
The use in special, character- or quest-specific, occasions (like notes, etc.) is OK, but there must be a public and easily accessible dictionary at least, in order to not exclude players. It would be better to immediately provide the translation in brackets, and let the reader decide if / how well they understand it. I've come accross one player who does this (though IIRC with elvish).
Therefore, I think
As long as you're not writing out paragraphs
should be more like "as long as it's just a few words at a time".