Found a strange problem. When I am playing campaign, in movies subtitles are not showing. But if I will change resoltion to 4:3 ratio in video options, like 800x600 or 1280x1024, subtitles will appear. When I change resolution back to my 1680x1050 or another not 4:3 ratio, subtitles will disappear.
I was tried to find positions of subtitles in source code. I found something in Shell\scripts\ifs_meta_top.lua but this file is not in shell.req, so it not compiling. Another search gave nothing, I only found Common\mission\*.mcfg files, but they, I think, have only start/stop time of showing subtitles.
Can you help me in my searches? I want to build user_script that will move subtitles for not 4:3 ratio resolutions. Is it possible? Sorry for my bad English...

I did a quick search any didn't find anything helpful. Maybe the subtitles are managed by the exe. You could try changing the size of movie in ifelem_shellscreen_fnStartMovie() from Common\scripts\ifelem_shellscreen.lua. Maybe shrinking the movie to a 4:3 ratio will bring back the subtitles.

While not perfect, your English is easily understandable. There are only a few minor mistakes.

Found that ifelem_shellscreen_fnStartMovie() function calls very often in Shell, but changing it in Common\scripts\ifelem_shellscreen.lua does not affect.
Found one commented string "-- resize to 4x3 section in center of widescreen" in Shell\scripts\ifs_tutorials.lua. Changing this code gave nothing too.

Also I noticed that loading screen of campaign missions has offset to top of text on not 4:3 ratio resolutions. Maybe the subtitles just overlap by the movie because they offset to top too?
In map's campaign scripts movies start with ScriptCB_PlayInGameMovie() function, so it is a game standard function, maybe as you said the subtitles are managed by the exe...

If I will change some parameters from .mcfg files, text will be modified:
Font("gamefont_small") - Font type
Color(255, 255, 255, 190) - RGB color and Zpos.
Tried to set Zpos to max, text doesn't appear, so, I think, on widescreen subtitles apper under the screen. Sadly =(