lisp's syntax is simple - its just parenthesis to define a list, first element of a list is executed as a function.
but for example a language like C has many different syntaxes for different operations, like function declaration or variable or array syntax, or if/switch-case etc etc.
so to know C syntax you need to learn all these different ways to do different things, but in lisp you just need to know how to match parenthesis.
But of course you still want to declare variables, or have if/else and switch case. So you instead need to learn the builtin macros (what GP means by semantics) and their "syntax" that is technically not part of the language's syntax but actually is since you still need all those operations enough that they are included in the standard library and defining your own is frowned upon.
Lisp has way more syntax, that doesn't cover any of the special forms. Knowing about application syntax doesn't help with understanding `let` syntax. Even worse, with macros, the amount of syntax is open-ended. That they all come in the form of S-expressions doesn't help a lot in learning them.
but for example a language like C has many different syntaxes for different operations, like function declaration or variable or array syntax, or if/switch-case etc etc.
so to know C syntax you need to learn all these different ways to do different things, but in lisp you just need to know how to match parenthesis.
But of course you still want to declare variables, or have if/else and switch case. So you instead need to learn the builtin macros (what GP means by semantics) and their "syntax" that is technically not part of the language's syntax but actually is since you still need all those operations enough that they are included in the standard library and defining your own is frowned upon.