Th

Th is an esoteric programming language consisting of one named pair of values, created by User:Scan in 2008. A value is again either a named pair or an atom. Is it similar to Lisp, but the length of a list is fixed. Thus, a pair represents an atomisable value itself, meaning a pair is just a thing to be evaluated. Eventually, a Th program is pretty simple.

Types
Th is not type-safe. Every atom is seen as an atom. The programmer is supposed to watch what they're typing.

Predefined pairs
More to come (I appreciate suggestions).

Hello, world!
print("Hello, ", "World!")

This is equivalent to:

print("Hello, World!", nil)

Addition
print("a + b = ", +(read("a = ", "\n"), read("b = ", "\n")))