me: would you like to have feathers, Grace?
Grace: (after a pause) Daddy, why did you say I can have feathers?
A couple of cool things here. 1. Grace used the verb "say" to indicate the presuppositional content of what I said (i.e. to mean "imply"). 2. Grace heard "would" in the polite sense whereas I meant it in the hypothetical sense -- polysemy exists in way more places than just word meanings.
In case it's unclear, let me spell out the intended and understood meanings of my sentence:
intended: imagine having feathers -- what would that be like?
understood: Have some feathers, if you please.
Grace's misunderstanding seems unlikely because I tend to think of the hypothetical meaning of the conditional as primary. Thinking about the history of language, this seems true -- the tense serves for talking about possible but not-yet-true realities, and has then been ritualized in polite forms in which we ask indirect questions rather than make requests of each other. But of course in the world of a toddler, indirect questions are much more common than hypothetical situations. My first thought on hearing Grace's response was that Grace may not understand the hypothetical meaning of the conditional at all -- she may know it only as the form we use for polite requests.
This is something I often see when we ask Grace to rephrase a demand in more polite language. Like most parents, we are merely expecting Grace to say "please." But often Grace rephrases without the please, but using the more polite indirect form.
Grace: Bring me milk Daddy, right now!
Me: Grace, can you ask for that more nicely?
Grace: Would you bring me milk right now daddy?
Me: Can you be a little more polite?
Grace: Would you bring me milk right now daddy pleeeeeeease?
Of course, the "would you" transformation is probably a more important bit of learning than the "please" bit. Now to figure out how I'll know when she's actually learned to use hypotheticals...