So far I understood from Piotr, the methathesis is a phenomenom which happened in all slavic langauges , but in different period of times for each slavic language. I am not sure if I make a mistake here, but the south slavic methathesised the words somehow in the VIII century.It was said, the romanians and albanians got the slavic words from slavic bevore the words were methathesised by south slavics.So the rom. and alb. "dalta, balta" are the slavic words dlato, blato and the explanation fits.

I have a problem with this aspect:Rom. gârba= slavic grUbU, rom. vârSa= slavic vreSa, rom. hârciog= slavic hroCegU, rom. bârlog= slavic brUlogU.

The problem is that the hungarians have these words too. And they are without methathesis.So we have:In hungarian: görcs, görbe, vorsa, hörsök, borlog

The name of the lake Balaton is derived from Balta and there is too , no methathesis, otherways we should have had Blaton.When we speak about hungarian, we are already almost in the X century and this doesnt fit anymore with the explanation for dlato= dalta and blato= balta

Which should be then the explanation?