That is still an open question, but I've already learnt something. At the start of only the second sentence, I suddenly understood why the short form of the past tense is used when writing in Welsh. Without it, just about every sentence would begin with the word "Wnaeth". In speech, these things slide by unnoticed and anyway conversation is peppered with "you know" and "by the way" and "to tell the truth" and other such filler phrases which disguises the fact that you're using the same verb pattern over and over. People therefore only tend to use the short form past tense for a few common verbs, such as to speak or to go, but in writing, you need the variety.
(Crossposted to LJ and Dreamwidth. If you want to comment, please feel free to do so at whichever site you find most convenient.)