Word-for-word quote of a completely out-of-the blue utterance:
“Daddy, is this true? If there were giants, then a football to them would be the same size as a pea to us.”
The “if…then” construct is what is known as a counter-factual conditional – If [something that is not in fact true] then [something else that is not in fact true], and to correctly construct such conditionals you use subjunctive verb forms (were… would be…).
What amazes is that somehow, without any explicit instruction at all, Lillian can spontaneously construct counterfactual conditionals.
But what really amazes me is that somehow she’s acquired the conceptual capacity to talk about the truth value of counterfactual conditions. (Aside: in some of our workshops we teach professionals such as intelligence analysts to try to avoid talking (i.e. thinking) about truth of conditionals since it is so much more cognitively demanding than thinking about regular statements.)
No wonder linguists have argued that humans have a kind of innate capacity for language acquisition.