"Prynhawn dydd Gwener"
Why is Tuesday morning bore mawrth (no dydd in the middle) but friday afternoon has a dydd in the middle?
This must be a mistake, Chris. Mawrth is also March, so perhaps it was confused for "March Morning"?
After several unfair questions in a row, where I'm asked to guess which of two days of the week a new Welsh word refers to, finally my knowledge of Latin fails me. So where does ’Gwener’ come from?
So it comes from Latin like the others, it's just less recognizable? I guess that I can see the Latin root in there.
Yes, you can see the "(g)wen-", and, if.w=v, then "ven-." I'm not sure that was the right way to write that, but you can probably see what I mean.
This is optional - 'Sul' etc. is always capitalized, however it is your choice whether you capitalize the 'dydd'. However, I choose to always capitalize the 'Dydd', because as 'Mawrth' is also March, I believe that it is right to grant the whole word - or phrase - as a name; a proper noun.