Note: This question may contain wordings that may be considered rude to some, so proceed with open mind and caution.
One of the legacies of Japanese colonization in my country during WW2 is a rude slang name-calling word "bagero" which roughly means "stupid bastard", which I could easily map to the similarly sounding colloquial phrase バカヤロウ soon after I started learning Japanese. The people at that time probably could not make out what they heard and simply understood the interjection as "bagero".
However, I am still wondering if the "bagero" version really came from the people mishearing "バカヤロウ", or there was a dialect that really pronounced バカヤロウ as バゲロ. Was there?
There is also a longer version of the localized interjection, "bagero kuntoroyo", that I still cannot decipher until now. Can anyone suggest what would be the original Japanese bad words, if any?
N.B. My purpose of asking this question is not to learn about the bad words, but simply out of curiosity about this phrase that are (fortunately becoming rarely) used by local people here who are oblivious of its actual meaning.