At this point, Glorio might as well chose to betray them after Goku started to mispronounce his name every time. For a second, I actually thought Goku would get it right after Glorio taught him again.

Could be that Bulma just approached it in the wrong way, but she did work on Namekian ships before. I guess they had to have these ships prior to leaving the demon realm to, well, leave. But then again, maybe Namekians wished themselves out of the demon realm or something and created their own tech afterward.