My daughter asks about animal sounds all the time and has recently become obsessed with giraffes.
Do giraffes make noises? If so what does it sound like?
This reasonably authoritative-looking site says “only low moans or bleats”.
So…what?
Giraffes sound like pron stars? 
You can listen to a recording of giraffe sounds here. A player capable of playing Real Audio media required (I recommend the Realplayer Alternative; the RealPlayer itself is crapware.)
Thanks Q.E.D., she’ll be thrilled!
Is that frequency shifted or something? To me, it sounded like a thin metal door slamming shut twice.
Yeah, that didn’t sound like an animal sound at all.
-FrL-
My mother called the zoo to ask them that question, when 5-year-old me asked it. 
Their answer was “sort of a low grunting noise”.
I think we know the reason that there isn’t a “giraffe” verse for the “Old Macdonald” song.
According to Zoo Tycoon they make a strange rumbling growling noise…
On the other hand, you should see and hear the precision nine-giraffe clog-dancing team! 
In college I worked at The Wilds, a wildlife preservation and conservation facility in Southeast Ohio. At the time, they had several reticulated giraffes - most notably a mother and child. The oddest thing about that place was that in the winter, the giraffes were housed in a building like a giant garage. There were no bars - you’d just open an small side door and surprise - there they were, meandering about. The baby was super-friendly, and I oten traded shifts with other employees to get more time with the giraffes (the rhinos too, actually). Of course, that time was spent mainly cleaning up giraffe dung and laying down straw, but as there were no enclosures, it still meant plenty of time interacting with them. I have some great pictures of me standing with the baby - I’ll have to go look for them.
Anyway, long story short - they usually make a sort of grunting noise and occasionally snort in the same manner a horse does.