Hello Rosetoast and welcome to Intro class!

Congratulations on your lucid dream! I've come accross other people's accounts of lucid dreams feeling very realistic and vivid, and then having the opposite impression upon waking. I think it has to do with dream recall and overall mind agility. So, to improve the impressions be able to practice overall dream recall. Also, dreams may fade if you have other dreams after that. This is pretty normal and not much can be done unless you wake up immediately after your lucid. Overall excercises to improve mind agilily would be meditation, visualization, ADA, and selective recall of events (try recalling random past events during the day with as much detail as possible).

About having issues with voice, this is somewhat common and happens to almost everyone every once in a while. I think if you get more ld practice, there will be also more instances where you will be able to speak.