How to post a listing for a coding project for a hedge fund

I need to know what’s reasonable to ask for when listing a coding job. I created a listing on freelancer for a job creating an algo for my hedge fund. The issue is my trading platform uses it’s own coding language. I’m trying to learn some coding but i know very little so i don’t know if its reasonable to require someone who will create the algo within the language it will run in or if i’ll need to get it done on a similar language, then go back to my platform and have them rewrite it using their language. It’s possible to do that but of course it’s not what i’d prefer. Is it reasonable for me to say “it’s in the language of my platform and you’ll need to learn to code it in this language” or is that an extreme thing to ask? How would you handle it if you were asking someone to do it? One of the first things it says in the scripting guide is that it would help if the user was proficient in C. So would it be more reasonable to ask for a programmer to build something in a more common language like C or Phython then I bring it to my platform to decipher it, or is it reasonable for me to expect a programmer to figure it out? I just don’t know how things are done in this world. I’ll add a link to the listing just in case anyone wants to check it out.