Text-To-Speach (TTS) with a free and really good natural german male voice. The creator explains how it can be used. So this solution is a ecosystem and not just the voice itself. "Thorsten voice" is just the voice model. The solution (python tts) can be used with other models - so different languages (english, spanish and other languages). The website of "Thorsten voice" and its youtube videos explains it really good how to install it. Transforms text into speach e.g. as wav/mp3 file. Totally offline without accounts, without registrations etc. Straightforward. Website offers different ways for TTS. Created file can be used for open source projects or even commercial uses. Please check website (in english and german) or github (in english) for further information. Python is required. Installation totally via PIP (Python installer). Please see the Youtube videos (linked beneath or on the website). The videos on youtube shows each step to install it. Particularly suitable even for beginner. Easy step by step introduction. Please use subtitles in the youtube videos for english or other languages. The website contains additionally video for installing on mac (os x) and raspberry pi. Websites offers different moods how the speach will be produced: angry, whisper, drunken, happy etc. For linux there are additional information on https://wiki.ubuntuusers.de/Thorsten-Voice/ (german only) where I found it. I'm just a fan of that solution, not the developer/speaker.