“…Applying complex network models to study the dynamic features of language systems has become popular in recent years in fields such as language evolution/change and language development [ 2 , 28 , 29 ], quantitative linguistics [ 30 , 31 , 32 , 33 , 34 ], and language acquisition [ 21 , 35 , 36 ]. With regard to word co-occurrence networks, there have been many studies [ 29 , 30 , 35 , 37 – 39 ].…”