“ubuntu” is a southern and/or eastern Bantu word … one of those words that is found in a number of languages and that no one is quite sure of the origin of. But this does not mean that it can’t be pronounced correctly.
There are very straight forward rules of pronunciation for Bantu words in general. Especially in Eastern and Southern Bantu languages (of which there are hundreds) you can think of the vowels as always being pronounced the same way whenever and wherever they are encountered. There are not really any silent vowels, and although there is some elision, there is very little. In the case of “ubuntu” all the vowels are separate so that is not an issue. And all the vowels in “ubuntu” are the same vowels, therefore, they are all pronounced the same way.
Here is a Bantu vowel pronunciation guide that you may wish to clip out and keep in your pocket:
a like “ah” such as “Ah, I see. Roosevelt’s dog’s name was fala. Aha!”
e like “ey” such as “Ey, how boot a Molsen’s, ey?”
i like “eeek!” such as “This is good shit, mon” in a thick Caribbean or Mexican accent.
o like “oh or “toe” such as “No. Which part of ‘No’ do you not ‘Know'”
u like “oooo” such as “Desmond Tutu does not wear a tutu.”
There are not really alternative pronunciations for these vowels. Just pronounce them as specified here and you’ll be fine. In truth, when you put a vowel between some consonants or next to some other vowel, it will get pronounced slightly differently, but your mouth, tongue, and larynx takes care of that for you. Just follow the guide above until it is internalized.
So, for example, a common Eastern Bantu (KiSwahili) greeting is:
Tutaonana, habari gani?
Which is pronounced (to an English speaker):
Too Ta Oh Na Na, Hah Ba Reee Gah Knee
Tut own anna, hey berry gain ee
So, the vowels in “ubuntu” are simply:
Ooo , ooo, oooo
Like that kid on Welcome Back Kotter:
“Ooo, ooo, ooo, Mr. Kotter! Call on me!”
Then you stick in the consonants and the rest is pretty obvious:
Ooo (as in “ooo ooo ooo, I know the answer”) .. boon (as in Daniel Boone) … too (as in “me too!”).
Ooo boon too… ubuntu.
Not Ooo bun too
Not Ooo boon toe
Not oo bun toe
Just ooo boone too …. ubuntu.
But what does it all mean? Ask this guy: