Some relevant info:
- At the time of the unintentional build release, only one of the eight characters had complete voice acting in the game (Adalyn). Four other characters (Celeste, Yumi, Male/Female Slimes) had a small portion done for the game's demo, but not the majority of their lines.
- Yes, voice acting usually happens late in the development process, but it is not the only thing that happens late. I still have other things to work on, such as coding the movement of visual assets during scenes, arranging translations into languages besides English, writing more music for the game's soundtrack, and more.
- Voice acting is fairly simple as a concept, but I do think you're underestimating the amount of time and effort it takes, especially for a novel-length game. There are over six thousand lines in the game, and after each one is recorded, I need to listen to them, pick the best take for each line and/or ask for retakes with changes, and edit/balance the audio so it sounds good. Once I have all the lines done, I sort and process them into the game, coding it to play each line at the correct time. I'm also figuring out the code for playing wordless moan loops during sex scenes while the lines aren't playing, which takes extra effort.
I don't want to say you "know nothing of video game design and can't understand how tedious the process is", but it is time-consuming work, I'm a one-man dev, and VA is not the only thing vying for my time and attention. I can only ask for your patience, and assure you that I'm trying to get it done as fast as possible without sacrificing quality and/or driving myself insane.