What did Stitch say when he laughed after the arrival in this scene:
The language Stitch speaks is Tantalog. It is a combination of Hawaiian, Chinese and Chezcreekian.
I think he is saying something along the line of "I came, I saw, and I conquered." I don't know the exact meaning, but here are some dictionaries:
This transcript says it's just alien language
Maybe send me an angel...
the nicest angel you have.
(shouting in alien language)
According to the quotes on IMDB
Stitch: Poocha Chubugga Oom Chickee! Ha ha ha ha ha ha ha ha ha!
The alien language is used many times in the movie, but it's never translated. Most times we can guess the meaning by the situation or other people's reaction.
I have looked online, where people have made translations for the language, called Tantalog, but I couldn't find anything for this phrase or any of the words.