Is Welsh a Celtic Language?

Welsh is an Indo-European language in the Celtic family. The Celtic languages are actually surprisingly strange compared to their relatives. In fact, Irish is so strange that for a while people weren't sure it was an Indo- European language. There's basically suffixes that agree with person and number. So you have Arnaf, Anmi, Arnam, Anas. And then this sort of lessons thing that we found on Middle Welsh has it, has a chapter 15. It's all prepositions.