SubTTS 0.4 for Mac was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. This free Mac application is an intellectual property of Peter Ljunglof.
The application lies within Audio & Video Tools, more precisely Players. According to the results of the Google Safe Browsing check, the developer's site is safe. Despite this, we recommend checking the downloaded files with any free antivirus software.
From the developer:
SubTTS is an application that reads a movie subtitles file, and uses the built-in speech synthesizer to read the subtitles aloud while you are watching the movie. The program is a standalone "Menulet" - namely, it is a program that sits in the menu bar and talks to your favorite video player.
You may want to check out more Mac applications, such as FMrobot, SideShow or Flip4Mac WMV Player, which might be similar to SubTTS.