"Merch yw hi."
Translation:She is a girl.
From what I've been told elsewhere 'yw' is used more frequently in the south, but it's actually general.
Nothing, but we start a sentence with a capital letter in Welsh, as in English. Duo usually doesn't bother about capitalisation, but once in a while it seems to for some reason - a system problem, not anything that the course teams have any control over.
I have the same question. When asked to translate "girl" to Welsh, I typed "Merch" which was marked wrong. But when I later tried "merch" (the only difference was a capital M), it was right. I STILL don't understand that if they are spelled the same, why one is correct and the other is wrong.
As I explained above, the capital makes ni dufference to the meaning. It may be a Duo system bug and nothing that the course team can fix.
If it happens again, please raise a 'Duolingo bug report' so that Duo staff will be aware of the problem.