[cpeterso]

Very interesting language!

Why are numbers quoted? It seems that many of the quotes could be optional (except when needed for parser disambiguation). From your examples:

  age is 1
  name is Mary
  friend is isla

You could also use '.' as an optional command delimiter (in addition to newline) for more prose like, such as:

  age is 1. name is Mary. friend is isla.

[maryrosecook]

I like the period idea. I will try it.

Quotes are required around number literals to maintain consistency with string literals.

[Nzen]

I'm partial to the advice to designate strings by the vertical bar instead of quotes. eg, write |Hello | input_name |. Nice to meet you|. This avoids the complication of escape formats until much later.