Uhm, fiddling with the audio samples and recycling one single vowel to produce all the required one by simply freq. shifting with the NCO was an interesting experiment but it definitely fizzled. As in, it just did not work!
I am also disappointed by the results of my (lazy) attempt to re-target to the word "Hackaday". I should either take it more seriously and re-sample new vowels/consonants that are more appropriate for the target word or stick to the original "message". After all there is a whole lot of nostalgia that goes with that (albeit that would apply only for me :) Will revert the "segments" table shortly.
Minor hw update as well. I have separated the PIC10F board from the proto area (that I immediately re-used for another project) and re-soldered the pushbutton (SW1) notably missing in the early pictures... Also added a semi-proper connector for my scope probe and the audio amplifier (just headphones actually).
1 - Be humble. As rudimentary as my audio sample collection/manipulation was 20+ years ago, it was nonetheless somewhat optimal for the target.
2 - NCO peripheral definitely useful for future little tricks. I will explore possibility to freq. shift in WAV-1K project when playing back from an SD card...