2.5 Discussion of grammatical acquisition
2.5.2 Morphological and phonological agreement overgeneralisations: insights into
42 strategies of acquisition. She posits that, because in isiZulu all singular prefixes are either i- or u- commencing, children learn a system that is “superficially more transparent” than that encountered by Sesotho-speaking children (Suzman, 1996: 100). She says that isiZulu-speaking children are confronted with a range of i- commencing nouns, which gives them the tendency to overgeneralise the Cl. 9 prefix (or pre-prefix, in line with Herbert’s (1978) analysis that reanalyses the nasal of Cl. 9 as part of the stem). A Sesotho-speaking child, on the other hand, may tackle being confronted with prefixes commencing with different consonants, vowels, or zero morphemes by using a filler syllable identified as a shadow prefix, a partial prefix, or a place holder morpheme (Suzman, 1996). She says that consonant-commencing prefixes make the NPx less accessible to the child, and they resort to placeholder morphemes (Suzman, 1996). This is in line with findings of Tsonope (1993) who observes shadow vowels but no overgeneralisations of the NPx. Results of Suzman’s (1996) study show that the primary determinants of variation in patterns of acquisition across Southern African Bantu languages are the morphophonological properties of surface input.
Manner of NPx acquisition, summary: Overgeneralisations are unlikely to be semantically driven. The acquisition of NPx seems to occur through an interaction of morphological, phonological, and prosodic features, although the extent to which each of these factors dominates, remains unclear. This is in line with Yang’s (2000: 234 in Dowling and Gowlett, 2016: 301) alternative view that child language is not just an imperfect version of adult language but what he terms ‘a variational process’ in which children must adopt assumptions about how language works – assumptions which then change as new evidence is presented from their speech environments.
2.5.2 Morphological and phonological agreement overgeneralisations: insights into
43 2.5.2.1 Subject markers
Gxilishe, de Villiers and de Villiers (2007a) review theories of agreement and the way in which a child may come to produce the correct subject agreement on a verb. They theorise that subject marking may either be direct, which involves copying of the noun prefix onto the following verb, meaning noun prefixes have to be acquired first (known as the direct copy theory); or independent, which suggests that there is no relationship between the acquisition of subject agreement marking on the verb and NPx (Murphy, 1997 in Gxilishe, de Villiers and de Villiers, 2007a: 115). However, they state that “subject noun marking should be present when subject agreement is marked, because it is generated in the lexicon and reflects the same noun class that dictates the subject agreement” (Gxilishe, de Villiers and de Villiers, 2007a: 116). But, since noun class marking is an inherent feature of the noun, even in cases where the NPx may be absent, subject marking may still occur (Gxilishe, de Villiers and de Villiers, 2007a). For example, children may only produce umama ‘mom’ phonologically as mama but from input know that it is a Cl. 1 noun and thus correctly use the subject agreement marker. This in fact accounts for 31.8% of cases observed when Gxilishe, de Villiers and de Villiers (2007a) study spontaneous speech samples of children between the ages of 1 and 3;3. There is no difference at any age in the possibility of the child supplying the agreement whether the subject was explicit or not, their results thus debunking the direct copy theory (Gxilishe, de Villiers and de Villiers, 2007a). This is in line with findings from Kunene (1979), Suzman (1991) and Demuth (1988, 1992) that subject markers can appear before NPx. Gxilishe, de Villiers and de Villiers (2007a: 118) moreover note that subject marker substitution errors are “vanishingly rare” with 97.2% of errors being errors of omission. This is in line with subject agreement acquisition in Sesotho and Siswati (Demuth, 2003 in Gxilishe, de Villiers and de Villiers, 2007a: 118).
Suzman (1991) notes an overgeneralisation of a- as a cover term subject marker but comments that it is a form also used by adults when speaking to children. Suzman (1991) suggests that this could be the present tense disjunctive form -ya- with a zero subject marker, with the -ya- contracted to -a-. Demuth (1992) similarly suggests that the shadow vowel in Sesotho subject markers may stem from the Sesotho disjunctive -a-. Suzman (1991) notes this as a similar process to subject markers such as si- and li- being contracted to i- in the present tense conjunctive form, emerging as overgeneralisations of the Cl. 9 subject marker i-. She says this could be because the majority of nouns that children use come from classes in which the prefix contains i-, and they thus create what she terms ‘morphological paradigms’
44 around frequently occurring classes (Suzman, 1991: 48). But whether this is due to poor phonological differentiation or actual mis-assigning of class marking remains unclear (Demuth, 1988).
Additionally, Suzman (1991) observes children using i- as an alternative for the first person subject marker ngi- as well as for the Cl. 1 subject marker u-. Idiata (2005) notes how this is what Criesels (1991 in Idiata, 2005: 99) calls ‘echoes’, meaning that essentially the child treats subject markers as pronouns rather than agreement markers at the stage that this overgeneralisation occurs, generalizing highly salient pronouns. More research is needed regarding whether shadow-vowel subject markers indicate overgeneralisation of classes or are simply morphological place holders (Demuth, 2003). Demuth additionally (1992) notes that despite subject markers being well formed somewhat before the age of 3, there is nonetheless evidence of phonological ill-forms, for example, te a instead of ke a ‘I am’
(disjunctive form).
2.5.2.2 Other agreement markers Object markers
Suzman (1991: 77-78; 1999: 139) finds the overgeneralisation of the third person, Cl. 1 object marker -m- to Cls 2 and 9 at age 2;2 but only with only the disjunctive form -ya- and no subject marker (e.g.
yambona instead of uyababona ‘you see them’). However, once the Cl. 9 object marker is acquired by 2;4, the child in her study begins to overgeneralise that object marker to other i- commencing classes.
She posits that as with subject markers, this is a failure to associate the object marker with specific NPx (Suzman, 1991). Kunene (1979 in Demuth, 1992: 606, 2003: 219) finds that Cl. 3 object markers are being overgeneralised to Cl. 1 (see also Dowling, Deyi and Whitelaw, 2017) and Cl. 11 object markers are being overgeneralised to Cl. 5 in the speech of children aged 4;5-5;11. One can expect that if older children are making such errors, younger children would too. Demuth (1992) says this suggests that children do make phonologically based generalisations, collapsing phonologically similar classes.
Demonstratives
Demuth (1988) further notices an overgeneralisation of a Cl. 9 demonstrative for a Cl. 5 noun (child also aged 2;1) but drawing on her personal communication with Chimombo, who described child acquisition of Chichewa, speculates this may be due to a lack in phonological ability to produce distinct forms, particularly the ‘l’ sound which would indicate the appropriate Cl. 5 agreement at this age. This moreover seems to be the case as evidenced by the missing ‘l’ not only on the demonstrative agreement (produced as a glide instead, appearing in the same form as a Cl. 9 marker) but on the
45 conjunction le ‘and’ (with the ‘l’ deleted and pronounced e by the child) as well (Demuth, 1988). It thus appears the child is not overgeneralizing but underspecifying (Demuth, 1992). When this occurs, Demuth (1992) posits that the initial consonant either surfaces as a glide or is deleted altogether. This is a common phonological replacement in which children across languages replace a liquid with a glide (Oostendorp, 2016). The gliding of liquids is evidenced in isiXhosa by Maphalala (2012), who posits that glides emerge slightly before liquids, which is in line with findings from Tuomi, Gxilishe and Matomela (2001) in isiXhosa too. Liquids are acquired by the age of 3 in Maphalala’s (2012) data, although Grunwell (1997 in Maphalala, 2012) suggests that gliding of liquids can persist until the age of 5.
Possessive markers
Demuth (1988) notes overgeneralisation of Cls 9 and 10 possessive markers to what should be a Cl. 7 possessive markers at age 2;1, within a few utterances of the typical agreement. This occurs in both instances when no NPx was present on the noun (Demuth, 1988). She speculates this may be due to the large proportion of Cls 9 and 10 lexical items in the child’s vocabulary at the time or due to the articulatory ease of Cl. 9 agreement markers over others (Demuth, 1988).
Adjective markers
Suzman (1991) notes that despite being infrequently used, adjective markers appear in their concordally-correct forms. She posits this infrequency could be because “naturalistic conversation about ongoing activities and/or familial situations were not discourse topics that encourage elaboration and description” (Suzman, 1991: 73). This corresponds to her later statement that agreements produced are usually a direct consequence of what children talk about (Suzman, 1999) and implies that agreement for the noun classes produced most frequently (i.e. Cls 1, 5, and 9) may be acquired first. This parallels Harris, Golinkoff and Hirsh-Pasek’s (2011) first principal of word learning, namely: children learn the words that they hear most frequently.