This is one of those things Carter says now where understanding context is everything. He uses it for the words hello, pillow, bubble, and balloon. He is now learning to pronounce the latter two so I had to record his cute little jabber before it was gone. Eew is another "word" used for many. It means shoe, ew (as in yuck), and blue.
Ello-ello-ello!
-Carter
I thought a video might best portray this "quote." The best spelled version I could come up with is ello-ello-ello.