I've read Merlin before- its the one by TA Barron, right? Therefore, not a trilogy, there's 7 books.
Charlie Bone is nothing like Harry Potter! There's only like ten kids who can do magic, and its got a very twisted plot that streches through all 7 or so books now, and that's about all they've got in common, really. There's only one wand in it. Vastly different, I've never even thought about comparing them.
I used to be able to write in Greek... then I took up Dwarvish runes after LOTR, so i've totally forgotten them.
And I prefer Welsh to Gaelic, although they're very related languages.