I will vote for YES!

why? because sometimes spech is needed even in FP-S games like narrator's voice, online helper's voice, tutorial's voice or something and of'course RPG with dialogues.

If this will save memory and increase fps... why not?!?! Even if I don't need it right now, but when my game will be in final touch it will be usefull.
It's like a terrain generator.... some people need it someone not, becouse they are making space shooter, but it should be added

I hope You undarstand my Polish-English middle Atlantic language

The terrain editor/generator analogy is a pretty good one. Shaders is another. Some need it, some don't. Large amounts of speech are basically the norm in commercial games these days, but if you don't use very much speech then it probably wouldn't be a priority.

I'm creating a traditional, adventure game with a 129-page script (just for the dialogue and narration for the story portion...this doesn't include descriptions of objects, idle chatter when talking to someone during interactive portions, etc), and it would be commercial suicide to not add speech to the game. Back in the old days, you could d/l optional speech packs but this isn't the old days. I'm hoping Speex will pop up on the beta page sometime in the next weeks/months (hey, my behind the view negative numbers idea is in beta now so anything is possible ), so I'll just hold my breath, pass out, and check when I come to. Given the amount of speech I'll require, you can see why I have an interest in something like this.

If it never makes it in, there's always a 3rd party approach, and perhaps A.Russell will add it to his AL Plugin as he said he may someday. He's been gone for a while, so I hope he sees my post in his thread whenever he makes it back. I'll take either way...Conitec,, A.Russell, or someone else if I have to fork over a bit of green to make it happen.

I not renember well but think gamestudio support that.
but not all the windows versions? support adpcm compresion
in wav files (can be 4 bit audio, only for voice) and then the files are more small

"ADPCM Audio Codec" coming with all version of windows
probably you can save with audio software in that format
diferent types of compression if you like music but with very bad quality
but for voice are perfect, think the speex if for use if your program in other operating system, but gamestudio only runs in windows

Speex is a 3rd party format. It's stored in a spx file which is contained in the ogg file. 3DGS supports ogg, but it's for Vorbis audio only. Speex is a separate thing designed for voice compression only. They have a 3rd one called Theora for video compression, and it's supposed to compete with MPEG4. All three formats are stored in a ogg file. 3DGS only supports Vorbis at the moment, and I'm request for both Speex and Theora; however Speex would be higher priority for now.

Yes, I'm concerned about quality, as well as the final size. The best quality possible and the smallest size possible is the ultimate goal; however I would rank quality above size for my own purposes. My title features a large amount of speech, so I don't know if a compressed WAV file would be beneficial; however I know nothing about adpcm, nor if it is readable by 3DGS.

Even if you limit the quality of the WAV for voice, WAV is a horrible format. They are the bitmaps of sound, no compression. Speex is more similar to an mp3, better compression but with limited channels optimized for voice...

As I've stated many times, ogg supports Vorbis (audio), Theora (MPEG4-quality video), and Speex (speech) (and maybe others from http://www.xiph.org/). Ogg is simply a container. They also created the excellent and widely used FLAC lossless format. In fact, it's probably the most widely used of the various lossless codecs.