The amount of societal language input at home has been found to have a greater, negative impact on the HL than it has a positive impact on the acquisition of the societal language (De Houwer 2007; Hammer et al. 2009; Hoff et al. 2014). Furthermore, the effect of parental use of the societal language at home may be modulated by the proficiency of the input-provider (Chondrogianni & Marinis 2011; Goldberg et al. 2008). Whilst the differential effect of variation in input quantity on the (rate of) acquisition in many domains of language is undisputed, it is also clear that this relationship is non-linear in nature. In other words, threshold effects exist (e.g., Cattani et al. 2014; Gutiérrez-Clellen & Kreiter 2003; Thordardottir 2014) and not all linguistic properties are affected equally (Chondrogianni & Marinis 2011; Oller et al. 2007; Unsworth 2014, 2016b; cf. Hoff et al. 2012l; Paradis 2011). Research on the impact of variation in input quality has for the most part been restricted to studies on societal language development, with the notable exception of the studies by Place and Hoff (2011, 2015) and LaMorgia (2011). For example, it has been shown that input from native speakers is associated with more advanced vocabulary in the societal language, even after controlling for amount of input in that language (Place & Hoff 2011, 2015; see also Driessen et al., 2002). Furthermore, linguistically rich input (e.g., from different sources, including TV and reading) predicts rate of acquisition (e.g., Paradis 2011), and the number of speakers providing input is also a significant predictor of children’s (HL) development (Place & Hoff 2015). One other important aspect of HL children’s language experience is how much they use the language themselves. Indeed, children’s own HL use has been found to predict language outcomes in a number of studies (Bohman et al. 2010;
The amount of societal language input at home has been found to have a greater, negative impact on the HL than it has a positive impact on the acquisition of the societal language (De Houwer 2007; Hammer et al. 2009; Hoff et al. 2014). Furthermore, the effect of parental use of the societal language at home may be modulated by the proficiency of the input-provider (Chondrogianni & Marinis 2011; Goldberg et al. 2008). Whilst the differential effect of variation in input quantity on the (rate of) acquisition in many domains of language is undisputed, it is also clear that this relationship is non-linear in nature. In other words, threshold effects exist (e.g., Cattani et al. 2014; Gutiérrez-Clellen & Kreiter 2003; Thordardottir 2014) and not all linguistic properties are affected equally (Chondrogianni & Marinis 2011; Oller et al. 2007; Unsworth 2014, 2016b; cf. Hoff et al. 2012l; Paradis 2011). Research on the impact of variation in input quality has for the most part been restricted to studies on societal language development, with the notable exception of the studies by Place and Hoff (2011, 2015) and LaMorgia (2011). For example, it has been shown that input from native speakers is associated with more advanced vocabulary in the societal language, even after controlling for amount of input in that language (Place & Hoff 2011, 2015; see also Driessen et al., 2002). Furthermore, linguistically rich input (e.g., from different sources, including TV and reading) predicts rate of acquisition (e.g., Paradis 2011), and the number of speakers providing input is also a significant predictor of children’s (HL) development (Place & Hoff 2015). One other important aspect of HL children’s language experience is how much they use the language themselves. Indeed, children’s own HL use has been found to predict language outcomes in a number of studies (Bohman et al. 2010;
Unsworth_2017_Hbk_LangAttr_prefinal.docx