[Explaining it all to someone with no prior understanding will be difficult, but Ari will try.]

L-space is Lorentzen space. The hyperdimensional space described in Stanley Lorentzen's equations. Travel in ordinary space has a speed limit. You can't travel faster than the speed of light. Now, ordinarily we're travelling in four dimensions, yes? Three of space and one of time. If you use a Matsukata drive, you can transition your ship into L-space. Into higher dimensions. You travel at the same speed as before, but you cover far more distance. It's not a tunnel, or a wormhole, because you can move in any direction you want once you're in there. But everything looks very different, and there can be probabilistic fluctuations. It gives most people severe space sickness - disorientation, nausea, even hallucinations. The perceptual distortions can be extreme. It isn't a place human senses were designed for - but a properly trained spacer can resolve the distortions, mentally cut through them and be able to function in L-space. Where I've from, we've mapped out safe L-space lines between one star system and another, and that makes travel easier, and much faster.

Does that make sense? [If it doesn't, she's very open to answering questions.]