Between six and eight months, the child is sitting up and producing a number of difference vowels and consonants, as well as combinations such as ba-ba-ba and ga-ga-ga. This type of sounds production is described as babbling In the later babbling stage, around nine to ten months, there are recognizable intonation patterns to the consonant and vowel combinations being produced, as well as variation in the combinations such as ba-ba-da-da. Nasal sounds also become more common and certain syllable sequences such as ma-ma-ma and da-da-da are inevitably interpreted by presents as version of "mama" and "dada" and repeated back to the child.