The 'b' sound is a plosive too, by the way. It's voiced, vs the voiceless 'k'.
replyBut the place of articulation kinda flips, from rear consonant/front vowel (kiki), to front consonant/rear vowel (bouba).
If you flipped the voicing, it'd be 'gigi' vs 'poupa', which to my ears at least, is a lot less clear cut.
k is a plosive, not fricative: there's a discontinuity in the flow of air, not a friction-sounding continuous airflow. that fits your point though, regardless.
replyOops, you are right! Thank you for correcting. I checked before posting that some "k" sounds are indeed fricatives, but they definitely aren't in "kiki".
replyWell /b/ is also a plosive. :) Phonetics is out to sabotage your meaning.
replyIf I stick to the more familiar territory of bad speech synthesis on 8-bit computers using envelopes, /k/ probably starts with a burst of white noise.