Is two a plural marker in early child language?

Is two ever a plural marker in child language? By some accounts, children bootstrap the distinction between the words one and two by observing their use with singular-plural marking (one ball/two balls). Others argue that the numeral two marks plurality before children begin using numerals to denote precise quantities. We tested the relation between numerals and singular-plural marking in English-speaking 2- and 3-year-olds by asking them to label sets of objects. When children were not prompted to use numerals they hardly ever did so, although they did frequently use plural marking. Thus, it does not appear that children spontaneously use numerals like two as plural markers. Also, children who used numerals when labeling sets were significantly more likely to use a plural marker than children who did not use numerals, suggesting that most children view plural marking as obligatory when numerals are used, rather than viewing the 2 forms as alternative markers of plurality. Finally, two was no more likely than other numerals to be used with unmarked nouns (i.e., as an alternative to the plural), suggesting that it does not have a special status as a plural marker. We conclude that two is not a plural marker in early child language.