We used `params` because Method#parameters was what they called it in the standard library. I actually had it as `args` originally until someone pointed this out. https://ruby-doc.org/core-2.6.3/Method.html#method-i-paramet...
As for the syntax change, we are actually on our 8th iteration of the syntax. We really wanted this to NOT be a fork of Ruby so finding something compatible was very important. For example that's why it has the weird `sig {` syntax too, we didn't want to have to cause load-time and cyclic dependencies from adding type signatures.