months Most consonants are word-initial: They are the stops , , , and and the nasal . A preference for a front place of articulation is present. 21 months More phones now appear in intervocalic contexts. The additions to the phonetic inventory are the voiced stop , the nasal , the voiceless affricate , and the liquid . 24 months The fricatives , , and are added, primarily at the intervocalic position. 27 months Approximately equal numbers of phones are now produced in word-initial and intervocalic position. Additions to the phonetic inventory are the voiced stop and the consonant cluster . While the word-initial inventory now tends to have all the phones of the adult targets (adult production of the child's words), the intervocalic inventory tends to still be missing four consonants or consonant clusters of the adult targets: , , , and . Stops are the most common manner of articulation at all stages and are produced more often than they are present in the target words at around 18 months. Gradually this frequency decreases to almost target-like frequency by around 27 months. The opposite process happens with fricatives, affricates, laterals and trills. Initially, the production of these phonemes is significantly less than what is found in the target words and the production continues to increases to target-like frequency. Alveolars and bilabials are the two most common places of articulation, with alveolar production steadily increasing after the first stage and bilabial production gently decreasing. Labiodental and postalveolar production increases throughout development, while velar production decreases. Phonotactics Syllable structures 6–10 months Babbling becomes distinct from previous, less structured vocal play. Initially, syllable structure is limited to CVCV, called reduplicated babbling. At this stage, children’s vocalizations have a weak relation to adult Italian and the Italian lexicon. 11–14 months The most-used syllable type changes as children age, and the distribution of syllables takes on increasingly Italian characteristics. This ability significantly increases between the ages of 11 and 12 months, 12 and 13 months, and 13 and 14 months. Consonant clusters are still absent. Children's first ten words appear around month 12, and take CVCV format (e.g. mamma 'mom', papà 'dad'). 18–24 months Reduplicated babbling is replaced by variegated babbling, producing syllable structures such as C1VC2V (e.g. cane 'dog', topo 'mouse'). Production of trisyllabic words begins (e.g. pecora 'sheep', matita 'pencil'). Consonant clusters are now present (e.g. bimba 'female child', venti 'twenty').