.TTXT

.TTXT file extension

This is the basic program to work with .TTXT extension

Aegisub

Aegisub Aegisub Subtitle Script

Aegisub is an open-source application carefully designed to help you create, modify, correct, and synchronize subtitles in any language for your favorite movies and other video files. This feature-rich tool comes with all the functions required to produce high-quality professional subtitles in the most intuitive and straightforward way... (more)

The program works with the following extensions: srt, sub, ssa, ass and ttxt