These might also be loosely related (since bouba/kiki came up in the threads):

Why ‘Mom’ and ‘Dad’ Sound So Similar in So Many Languages - https://news.ycombinator.com/item?id=30605239 - March 2022 (1 comment)

Words known better by males than females, and vice versa - https://news.ycombinator.com/item?id=30275159 - Feb 2022 (650 comments)

Why spiky shapes seem angry and round sounds are calming - https://news.ycombinator.com/item?id=20830940 - Aug 2019 (21 comments)

Ability to identify genuine laughter transcends culture - https://news.ycombinator.com/item?id=17634212 - July 2018 (2 comments)

Molyneux's problem - https://news.ycombinator.com/item?id=16778983 - April 2018 (68 comments)

Distant languages have similar sounds for common words - https://news.ycombinator.com/item?id=12510720 - Sept 2016 (60 comments)

Are We All Synesthetes? - https://news.ycombinator.com/item?id=634989 - May 2009 (9 comments)

Oohs And Aahs: Vowel Sounds Affect Our Perceptions Of Products - https://news.ycombinator.com/item?id=54318 - Sept 2007 (4 comments)