Audacity could not start because of pango_font_description_set_size issue.
STEPS TO REPRODUCE
1. Install audacity (pkcon install audacity, or apt instal audacity)
2. run audacity from Terminal
3. There's an error, infinite loop.
(Audacity:14491): Pango-CRITICAL **: 23:25:13.271: pango_font_description_set_size: assertion 'size >= 0' failed
(infinite loop goes on..)
Linux/KDE Plasma: KDE Neon User Edition
KDE Plasma Version: 5.14.5
KDE Frameworks Version: 5.54.0
Qt Version: 5.11.2
Audacity(2.2.1 from Ubuntu repository) works well on Kubuntu 18.04 and 18.10.
Only KDE Neon has this issue.
However, there's a Snap package for Audacity the version of which is 2.3.0, works on KDE Neon.