Gake no Ue no Ponyo (theme song from Ponyo)

[Kattie41]

All of those sound effects are too difficult to translate! I think that they are all:

Peta-peta- sound of walking
Pyon-pyon- sound of hopping
Nigi-nigi- sound of grabbing (like a baby does)
Bun-bun- sound of shaking or swishing
Paku-paku- sound of taking big bites
Chuggyu -(edit) someone suggested this may be mixing "chu" (kiss noise) with gyu (grab noise). hmm?
Fuku-fuku- sound of sniffing
Waku-waku- sound of excitement

That's what I came up with using four dictionaries and the internet. But maybe someone else knows more what they mean?

Also, would it be best to leave them in Japanese with an explanation of meaning or to try to find English equivalents (onomatopoeias?). Does anyone know a good site for English sound effects as well? Or, if you know English sound effects well, please help me and I will appreciate you forever!

[Rei]

I think you should leave the terms in japanese, and then explain the terms in the footnotes. After all, it would seem rather strange if you wrote the english meaning in...just remember to number them, and then include the respective meanings. :)
If you want english sound effects...here are some suggestions, albeit not very good...>o<
Peta-peta- Step, step
Pyon-pyon- skip, jump
Nigi-nigi- squish (it has that effect on me, but it might be a little weird though)
Bun-bun- slosh, slosh
Paku-paku- bite, bite
*since it goes- "paku paku chuggyutsu". I think that the sounds might be combined. Like both have to do with eating/or with the mouth.
Fuku-fuku- this can remain as sniff. sniff
Waku-waku- wow, wow

Something along these lines, anyhoo. Hope it helps! ;)

[Kattie41]

Thank you so much! Wow, you helped me to understand a lot ^___^ I think that they sound better left in Japanese too!