Step 1 Choose the spelling alphabet
Step 2 Optional:
Step 3 Input the text to spell
Step 4 Optional:
Based on wikipedia.org
Install voice output:
Linux/Firefox:
Install espeak (does not work with snap-installed firefox)
Windows©:
https://support.office.com/en-us/article/How-to-download-Text-to-Speech-languages-for-Windows-4c83a8d8-7486-42f7-8e46-2b0fdf753130 (reboot required)