"An accident at sea would not be a good idea."
Translation:Fasai damwain ar y môr ddim yn syniad da.
Well a since Welsh is a Verb-Subject-Object language that is why it comes first as a verb. Secondly it is "Fasai" instead of "Basai" because it is a negative sentence which always has the letter of the verb mutated (if the letter mutates at all). This is because in traditional Welsh an untranslatable verbal particle was used to construct the negative which is now no longer used and instead "ddim" is placed in the sentence to make it negative, but the mutation remains. An example of the old method - "Na/Ni fasai damwain ar y môr yn syniad da."
Thanks for the great answer. I've slowly been getting used to "negative verbs soft mutate", but it's really interesting to know why. I think I've seen those negative particles in my brief forays into the William Morgan Bible.
Note that traditionally, negative verbs have a mixed mutation: aspirate if possible, soft otherwise.
So you would have "Ches i ddim gwin" for "I did not have wine".
But I think you hear "Ges i ddim gwin" nowadays as well, with soft mutation across the board for negation.
Yes, the soft mutation for all negatives, including TCP verbs, is becoming the norm in spoken Welsh, however the mixed negative is still considered the 'correct' form and is found in the written language and formal spoken language.