Qiu, C., & Winsler, A. (2015). Language use in a ‘one parent–one language’Mandarin–English bilingual family: noun versus verb use and language mixing compared to maternal perception. International Journal of Bilingual Education and Bilingualism, 1-20.

The most important finding in this paper is that the Mandarin-English bilingual kid (Ben) used more verbs in his Mandarin speech, but more nouns in his English speech. Since Mandarin is a verb-based language and English is a noun-based language, the different proportions of nouns and verbs observed in Ben’s Mandarin and English speech indicate that Ben might have achieved native-like language competence for both of the two languages. The fact that simultaneous bilinguals have native-like language competence in both of the two languages is not surprising. In fact, being competent in both languages is exactly what a simultaneous bilingual should be. However, much research on bilingualism has claimed that bilinguals are not equally competent in their two languages. The problem with some of the previous research is that they did not use “balanced” bilinguals. Qiu and Winsler (2015) incisively pointed out that the participant in their study is probably a “true” bilingual, because his parents had carefully planned it, and the one-parent-one-language principle was strictly executed.

This article touched upon several important issues in bilingualism and language acquisition in general. The first issue is the measurement of lexical development. Number of words and participants’ age can both be indicators of lexical development. Qiu and Winsler (2015), however, chose to use morpheme as the unit of MLU measurement, which is theoretically sound from a linguistic perspective. The advantage of using morpheme as the unit of analysis is that it takes into account morphosyntactic knowledge. The problem is that morpheme can be defined in different ways, and the acquisition of morphemes depends on some other issues. Although Qiu and Winsler (2015) did not describe their MLU calculation strategy in detail, I think there are at least two problems they must have encountered.

The first problem is the definition of morpheme. In this paper, a morpheme is defined as a unit of meaning. For example, “picked” has 2 morphemes, because “pick” and “-ed” both mean something. My concerns here are on the irregular words. For example, do we count “ate” as having 1 morpheme or 2 morphemes? Theoretically speaking, ‘ate” has 2 morphemes. One is the root “eat”, the other is the past tense reference. If a kid can use “ate” to refer to something he/she had in the past, we have to give the kid credits for knowing both the concept of “eat” and the concept of tense. To make things a little more complex, the third person possessive “her” (as in “Her book.”) might be counted as having 3 morphemes. “Her” contains a morpheme for person (3rd person), a morpheme for case (possessive case), and a morpheme for gender (feminine), all 3 of which contribute to the meaning of “her”, and are thus units of meaning respectively. In other words, the measurement of MLU measurement depends greatly on whether we treat morpheme as simply an affix or “a unit of meaning”.

The second problem lies in the acquisition of morphemes. For example, to count “picked” as having 2 morphemes, one has to show that “-ed” is used correctly and systematically. If “-ed” only occurs with “pick” but not with other verbs, or if “-ed” was used as something other than a past-tense morpheme, then we probably cannot count “-ed” as a separate morpheme. For example, Ben might be using “picked” for picking up a rounded object, but “pick” for picking up everything else, disregarding when the “picking” happens. In conclusion, I applaud the general principle that morpheme is more reliable in measuring lexical development than number of words or age, but one has to make some theoretical decisions when applying this principle in practice.

The distinction between noun-based and verb-based languages is new to me. I am, however, aware that Chinese kids learn verbs earlier than English-speaking kids. The reason is not that Chinese is verb-based, but rather the structural complexity of Chinese nouns. Chinese nouns have a classifier system that is much like the gender system in most of the European languages. One may think of classifiers as gender morphemes. German, for example, has 3 genders (i.e. masculine, feminine and neuter). Mastering German gender system is very hard, because gender assignment has little to do with sex and is semi-arbitrary (e.g. das Mädchen “the girl” has a neuter gender). With only 3 genders, German nouns are already puzzling enough to nonnative speakers. Now imagine a language with more than 20 genders. Chinese is such a crazy language. Unlike nouns, Chinese verb system is quite simple. It does not have much inflexion. No subject-verb agreement and no tense-marking either. It is, therefore, relatively easier for kids to acquire Chinese verbs than nouns.

Finally, there seems to be a discrepancy between the claims in the literature and the finding of this paper. The claims in the literature are that Chinese kids acquire verbs earlier than nouns for the reason that Chinese nouns are more complex (or Chinese is a verb-based language). The finding in this paper is that Ben uses more verbs when speaking Chinese, which does not necessarily imply that Ben acquired verbs earlier. The same discrepancy goes with Ben’s usage of English nouns. From a sociolinguistic perspective, one has to wonder whether Ben’s usage of verbs and nouns relates to the different activities he engages in with each of his parents.