There is no standard word in 4tH to concatenate strings. As a matter of fact, string manipulation is one of 4tHs weakest points. But since we are focused here on doing things, we will present you a word which will get the work done.
The word 'APPEND$' appends two strings. In this example string "one" holds the first name and string "two" holds the last name. String "two" is appended to string "one" to form the full name. Finally string "one" is printed.
: append$ ( a1 a2 --) count \ get length of second string dup >r \ move copy to return stack rot count \ get length of first string over over \ move copy to return stack >r >r + \ get addr of terminator swap cmove \ append second string 0 r> \ NULL char and addr on stack r> r> + \ get offset of new terminator chars + \ calculate addr of terminator c! \ store terminator ; 32 string one \ define string one 32 string two \ define string two " Hans " one copy \ initialize first string dup \ duplicate address " Bezemer" two copy \ initialize second string append$ \ append both strings count type cr \ print first string