DH has what I like to call, in my more diplomatic moments, a compressed range of emotions. Actually, I guess it's not really the emotions themselves that are in question, but rather the expression of them - he could be feeling any number of things in there, but no one has any inkling of it because the range of expression utilized is so impossibly narrow. Everything, from lasagna to lovin', is valuated on a scale of "not bad" to "pretty good".
People who are not in a relationship with someone like this might refer to it as stoicism or unflappable-ness or some other such poetic nonsense, but seriously, speaking as someone whom you might refer to as loquacious, this particular trait gives me issues. Like, hives, and irrational bursts of anger.
I have heard tell of a couple, recently shacked up, who were facing a similar communication barrier, and felt the need to create their own couple's lexicon. Brilliant! You could just post it on the fridge! It could go something like this:
She says "in a while"; she means "15-20 minutes".
He says "in a while"; he means "one to thirty-six hours, give or take".
She says "nothing"; she means "you had better bloody guess what's wrong and fix it pronto or you are so cut off for the rest of eternity".
He says "nothing"; he means "Jenna Jameson, but I have a vague instinctual sense that that would really piss you off and so I'm not going to say it".
The challenge, then, would be in the painful extraction of the male terminology. I think it would either have to involve slipping him some personality-enhancing narcotics, or just be executed via a protracted process of trial and error - "in a while", for instance, could vary depending on whether he's going out for poker night with the boys or promising to take out the garbage, but you'd just have to watch closely and take notes. Forever. Maybe issue revised editions of your couple's lexicon every so often to keep up with observed trends in usage.
Alternately, you could do like my mother does, and just interpret what you wish from the unintelligible grunts received in response to attempts at dialogue:
He says "Ungh"; he means "Why don't you go buy yourself some more really expensive shoes, honey? You deserve it!"
He says "Mmng"; he means "Amazing! Tell me more about your endlessly fascinating days at work!"
He says "Uh-uh"; he means, "Why don't you go to that shoe sale that's on now at your favourite store, honey? Shopping at sales is like making money!"
He says "Uh-huh"; he means "Perhaps you should remind me progressively more forcefully in five-minute intervals until I actually get off my ass and do what you asked!"
Actually, screw the lexicon, this way is way more useful. And was I complaining? What I meant was, thank goodness for stoicism, I totally needed more shoes!