Ruby & Javascript have syntax defined in their parsers for control structures. for eg:

  # Ruby
  if someThing() 
    doThis()
  else
    doThisInstead()
  end

  # Javascript/Perl/etc
  if (someThing()) { doThis() }
  else { doThisInstead() }

Whereas Io & Smalltalk requires no new syntax and uses objects & messages:

  # Io
  if(someThing, doThis, doThisInstead)

  # Io like Ruby,etc
  if(something) then(doThis) else(doThisInstead)

  # Io like Smalltalk
  someThing ifTrue(doThis) ifFalse(doThisInstead) 
  
  # Smaltalk
  someThing ifTrue: [doThis] ifFalse: [doThisInstead].

As an aside, Haskell wouldn't need syntax for something like `if', but has it as a convenience. There's no syntax for looping, you can do that with higher-order functions.