Yes it is possible to successfully translate probably anything into English and get pretty close to the meaning of the original and maybe a portion of the essence.
Pysgod a sglodion may well translate into fish and chips but if the original was written to account for the Welsh accent, dialect and multiple syllables then fish and chips in a Home Counties or Black Country accent and dialect won't translate very well at all.
Words in the end, are just words no matter what language they are written in. It's only when they are lifted off the page by the narrator, poet or singer that they can be given an individual expression, emotion or context. The essence is made up of all of these things.
I never said they couldn't be translated and I'm sure the translation you cite was a labour of love. However, I would still prefer to hear it in the tongue it was written in.