My intention was solely to counter the idea that using ":" to mean "is" or "is a" is somehow inconsistent with written English. I don't think it's always necessary or even desirable to match the use of symbols in programming with English orthography, in any case.

The use of a declaration with initialization as the example here muddies the water. Whatever syntax you use has to work for uninitialized declaration of variables, function arguments, and structure members:

  val breakfast: String
  fun serveBreakfast(breakfast: String)
  struct MealPlan {
    breakfast: String
  }

Declaration with initialization just needs to be consistent with these.