Table 4. A comparison of heritability estimates of language and reading skills in past twin studies and the present Chinese twin study.
| Past twin study | Chinese | |||
| Skills | Authors | Country | Heritability estimate | Heritability estimate |
| Word reading | Byrne et al., 2005a | Australia, USA | .70 | .73/.68CA |
| Byrne et al., 2007a | Australia, USA | .49 to .72 | ||
| Byrne et al., 2009a | Australia, USA, Scandinavia | .82 | ||
| Samuelsson et al., 2007a | Australia, USA, Scandinavia | .61 to .91 | ||
| Samuelsson et al., 2008a | Australia, USA, Scandinavia | .33 to .84 | ||
| Brooks et al., 1990b | USA | .45CA | ||
| Gayàn & Olson, 2003b | USA | .85CA | ||
| Keenan et al., 2006b | USA | .66.65CA | ||
| Hart, Petrill, Thompson, & Plomin, 2009c | USA | .45 to .94 | ||
| Petrill et al., 2006c | USA | .68.67CA | ||
| Harlaar, Dale, & Plomin, 2005d | UK | .63 to .74 | ||
| Vocabulary | Byrne et al., 2002a | Australia, USA, Norway | .18 | .11/.09CA |
| Byrne et al., 2009a | Australia, USA, Scandinavia | .44 | ||
| Samuelsson et al., 2005a | Australia, USA, Scandinavia | .32 | ||
| Hart, Petrill, DeThorne, et al., 2009c | USA | .29 to .49 | ||
| Mather & Black, 1984e | USA | .68 | ||
| Van Hulle et al., 2004 | USA | .08 to .20 | ||
| Dionne et al., 2003d | UK | .10 to .21 | ||
| Phonological memory | Byrne et al., 2002a | Australia, USA, Norway | .19 | .50/.51CA |
| Samuelsson et al., 2005a | Australia, USA, Scandinavia | .57 | ||
| Wadsworth et al., 1995b | USA | .95 | ||
| Kovas, Hayiou-Thomas, et al., 2005d | UK | .41 | ||
| Phonological awareness | Byrne et al., 2002a | Australia, USA, Norway | .52 | .08/.07CA |
| Byrne et al., 2005a | Australia USA | .63 | ||
| Samuelsson et al., 2005a | Australia, USA, Scandinavia | .60 | ||
| Gayàn & Olson, 2003b | USA | .83CA | ||
| Petrill et al., 2006c | USA | .48.30CA | ||
| Petrill et al., 2007c | USA | .14 to .59 | ||
| Hohnen & Stevenson, 1999 | UK | .52 to .62 | ||
| Kovas, Hayiou-Thomas, et al., 2005d | UK | .38 | ||
| Rapid Automatized Naming | Byrne et al., 2002a | Australia, USA, Norway | .00 to .66 | .42/.42CA |
| Byrne et al., 2005a | Australia, USA | .60 | ||
| Samuelsson et al., 2005a | Australia, USA, Scandinavia | .64 | ||
| Davis et al., 2001 | USA | .62 | ||
| Hart, Petrill, Thompson, & Plomin, 2009c | USA | .42 to .79 | ||
| Petrill et al., 2006c | USA | .77.72CA | ||
| Morphology/Grammar | Byrne et al., 2002a | Australia, USA, Norway | .31 | .44/.25CA |
| Samuelsson et al., 2005a | Australia, USA, Scandinavia | .29 | ||
| Orthographic skills | Gayàn & Olson, 2003b | USA | .87CA | .20/.06CA |
Note. Studies with typically-developing samples in the age range of 3 to 11 years are included in this table. Studies based on the same sample are denoted by the same superscript in the Authors column. In case of studies examined the same variable based on the same sample, the study with the largest sample in the analyses is included. Superscript CA denotes estimates with general cognitive ability accounted for. References for this table are given in Text S1.