We once had 5 who howled, yodeled, 'roo'd' and of course growled. It was glorious, every day my greeting was a 5-basenji howl-fest. It was a mother and 3 of her sons and unrelated female. It was a very vocal family unit.
Current dogs: Nicky, silent except for the occasional growl
Eddie, crowing rooster sounds on greeting, very occasionally.
Chipley, occasional barroo as a greeting, which we applaud and make a fuss over. Otherwise nothing. We do know he can scream, he did when he was attacked a few weeks ago!
All mine are rescues so lineage is unknown. I love noisy basenjis, but it can be rough on the neighbors.
1. Kipawa will do the 'once only' bark, which is more like an *ark. This only happens when someone comes to our front door.
Kananga will do that too, and only when I'm leaving. He gets all excited and will have his tailing waging, every once and awhile letting out a similar noise, a strange bark.
That and the usual yawn noises.
All of mine would baroo, but they were pretty stingy about it. I find Basenjis tend to vocalize when they are impatient or frustrated about something. One of my girls would vocalize if I "threatened" her by holding my hands over her head. My first boy would sometimes baroo, but was a wonderful howler. I got him started by making noises through an empty paper towel roll cardboard. He started howling and once he began he would keep it up for awhile. This became a behavior that was "on cue". He would howl if I sang his "baroo" song to him, and his other cue to howl was saying "You're nothing but a dog, and that's all you'll ever be". That would get him going, and I could even hold him upside down while he continued to howl. Too funny!
My current boy usually vocalizes if we are late with his meal or if we delay going out after loading his roller ball. He gets impatient waiting for us to leave, so he can have his treat. He will also join in if I start howling like a wolf.
Three of mine would give a fox bark, usually if startled. My current boy will give a bark at a stranger. My old girl would only put her fur up and "huff". All have had an impressive "snark" if disturbed when comfortable.
Ohhh I am going to have to try the paper towel roll thingy. I want them to baroo more maybe that is the trick? I will probably just get ****ed heads and the 'WTF are you doing Mom?' look.
When we had the rotties, Arwen would join them in howling but it was a truly freaky sound. Now, no matter how much we humans howl or how shrill, no response. 
And yes, Cara does the musical yawns.
Hope just does the musical yawns, yodels for when we come home and baroo's for every other thing. She also "talks back" when shes in trouble with a grumbly sound (i find it hilarous - i try not to show this though haha).
I have heard her scream and i have heard other basenjis argue scream when i take her back for visits to her breeder and the other dogs get impatient with one another and scream the place down.
I havent ever heard a sound that D.D.S. displays in her youtube vids come out of Hope.
LOL, when we got Sayblee and she made those noises, we said she was summoning her minions. I am just glad their actions don't match their noises!
Mister Puppy yodels a bit now and then, but not much. He's a very silent boy, but when he's very happy we can hear him say "RAFF!".
ROFLMAO, "raff"? Record it please. Arwen only said a clear loud R her first few years other than the occasional scream (like when Leora splashed cold water on her) and howling with the Rotties. It was pretty funny to us since I had named her Arwen (R win) before we got her.
The only sounds I can consistently coax out of Jake are the ones where he sounds possessed.
Step 1: Flip him on his back
Step 2: Tickle/Rub his spine area
Step 3: Wait for the demons
He'll make other noises when he feels like it but I haven't figured out the "triggers" yet.
