Table 1.

Age group (in months) where 55–65% of Mandarin and English learners have at least reached the one-knower stage, the two-knower stage, or the three-knower stage and age group where 25–35% had learned the cardinal principle.

Stage	Age group when criterion is met (in months)
	Mandarin	English
One-knower	30–32	24–26
Two-knower	36–38	30–32
Three-knower	42–44	Between 36–38 and 39–41
Cardinal principle	42–44	39–41