How to combine several audio files into one: free and fast method, and you don't need Audacity

I've been looking for a text-to-speech (TTS) service that would allow me to create bilingual or multilingual audio message in one audio file. This would be useful for emergency alert call out services, auto-attendant messages in telephony services, or even outgoing greetings on voice mail services.
Unfortunately, in 2022, one cannot download a bilingual message from a TTS service like Amazon Polly, Google TTS, or Microsoft TTS. The only way to generate a multilingual audio file is to download two (or more) audio files generated by a TTS service, place each on a single timeline in Audacity or Adobe Audition, and then save the project as a new audio file.
This works, but I wanted a quicker workflow. And I found it.
In this video, I will show you how to use the free application Sox to combine two or more mp3 audio files into one new audio file. This makes Audacity and Adobe Audition unnecessary for the task of combining audio files, and it creates the new audio file much faster.
It takes about 10 minutes to set up your Windows computer to do all this. But it's pretty easy to do if you follow the steps in this guide.
Also, if you need to convert that mp3 an audio file with specific settings, I will demonstrate how to use Adobe Audition watch folders to automatically convert any file that you place in a designated Windows folder. This is a huge time saver.
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INSTRUCTIONS SHOWN IN VIDEO
1. Create folder structure
2. Download Sox: sourceforge.ne...
3. Download libmad-0.dll and libmp3lame-0.dll: stackoverflow....
4. Add libmad-0.dll and libmp3lame-0.dll to the folder where SOX was installed to.
5. Add the Sox folder to your PATH. Go to My Computer → Properties → Advanced System Settings → Environment Variables → System variables. Select Path. Click Edit → New. Add the path where Sox is installed.
6. Open Notepad and enter this text: sox *.mp3 audiofile_EN_FR.mp3
7. Save the file in your work folder with the name: Merge mp3 files into one.mp3