Directly stolen but credited:
As employee #1 at Naughty Dog, I wrote about half the code for Crash 1. The sound effects for the game were done by Mike Gollum, along with Ron Horwitz and Kevin Spears, at Universal Studios.
The sound Aku Aku makes is gibberish and was never intended to mean anything. That said, various people on the Crash team (and our friends and relatives) interpreted Aku Aku’s little noise as lots of funny things, the most common of which (in my recollection, at least) was “Rutabaga”.
Incidentally, the name Aku Aku comes from a Polynesian restaurant that resided near the Alewife T Station when Andy (Gavin), Jason (Rubin), and I lived in the Boston area. It had a giant tiki statue out front and, as I recall, fairly terrible food. This spot is now occupied by Jasper White’s Summer Shack, and the tiki statue has been converted to a fisherman.
Here’s a picture of the original Aku Aku restaurant:
I wonder what they did with the other tiki statue…
Source: Dave Bagget (Quora)