Liz has been thoughtfull enought to include a rundown of the Japanese in her fic. For poor beginers such as me it's a kind gesture ^_^

Tenshi no Yume wo Miru: To see a dream of an angel. "Tenshi" is angel, and I use this word a lot. Aa: Really casual confirmation sound.
Daijoubu ka: Are you all right?
Daijoubu: I'm all right.
Iie: No. ne: this has a lot of translations, but in this case, it's sort of like "right?"
Nemui...ore wa nemui...: Sleepy...I'm sleepy...
Gomen ne: Sorry.
Kuso: Literally translated, "Shit" but in intensity it's more like "damn".
Eto...: Uh...
Ore: Masculine I/Me.
Dai suki Quatre, Ai shiteru: This is really complex. These both mean "I love you", but at different levels; dai suki is less intense then Ai shiteru. Ai shiteru is such a powerful phrase that the Japanese simply never say it, even after marriage.
Nan da!?: WHAT!?
Matte! Matte kudasai!: Wait! Please wait!
Boku mo suki da!: I love you too! This one is less intense then either dai suki or ai shiteru, however.
Koibito/koi: Lover.
Kami-sama: God.
Onegai!: Please!
Nani-?: What-?
Mochiron: Of course.
Ima yo!: NOW!
Zutto: Forever.
Wakaru: Do you understand? hontou ni dai suki:
Truly, I love you.
Oi: Hey!
Quatre wa doko?: Where's Quatre?
Ohayo!: Good morning!
Genki: Really casual way of saying "How are you?"
Genki: I'm fine.
Silencer: This is in English, obviously, but I just wanted to say I'd heard this term used as Trowa's nickname, just as Heero's is "Perfect Soldier."
Owarimasu: The end.