• Articulation norms  according to Goldman et al. (2000).  This explains at what age a child should be able to correctly produce a sound.
     
    Sound                           age for female                 age for males                    
    /m/                                        2 .0                               2.6
    /n/                                         2.6                                2.6
    /h/                                         2.0                                2.6
    /p/                                         2.6                                3.0
    /f/                                          3.0                                4.0
    /w/                                        3.0                                2.6
    /b/                                         3.0                                3.0
    /ng/                                       4.6                                4.6
    /j/                                          4.6                                4.6
    /k/                                         3.6                                3.6
    /g/                                         3.6                                3.0
    /l/                                          5.0                                6.0
    /d/                                         4.0                                4.6
    /t/                                          3.0                                3.6
    /s/                                          5.0                                5.6
    /r/                                          4.6                                6.0
    /ch/                                        5.0                                5.6
    /v/                                          6.0                                7.0
    /z/                                          5.6                                7.0
    /zh/                                         -                                       -
    /dg/                                        4.6                                5.0
    /sh/                                        4.6                                 5.6
    /th/voiceless                            8+                                  8.0
    /th/ voiced                              6.0                                 7.0