Human language is a complex system where words interact in non-random ways, enabling the creation of an enormous variety of sentences from a limited set of words. This process is fast and robust, and the co-occurrence of words in sentences reflects the organization of language in a subtle way that can be represented as a graph of word interactions. The study shows that such graphs exhibit two key features: the small-world effect and a scale-free distribution of degrees. The small-world effect refers to the short average distance between words, which is around 2-3, despite the large number of words that can be stored in the human brain. The scale-free distribution indicates that some words are highly connected, and their removal can significantly affect the network. The graph of human language shares properties with other complex systems, such as biological and technological networks. These properties suggest that language has an evolutionary and social history that influences its structure and flexibility. The study also shows that the distribution of word frequencies follows a power law, indicating that the most common words are highly connected and play a crucial role in language. This scale-free structure allows for efficient communication and flexibility in sentence construction. The research also explores the implications of these properties for language disorders. The removal of highly connected words, such as function words, can lead to communication difficulties, as seen in conditions like agrammatism. The study highlights the importance of these highly connected words in maintaining the structure and function of language. Overall, the findings suggest that the organization of language is a complex system with properties that reflect its evolutionary and social origins.Human language is a complex system where words interact in non-random ways, enabling the creation of an enormous variety of sentences from a limited set of words. This process is fast and robust, and the co-occurrence of words in sentences reflects the organization of language in a subtle way that can be represented as a graph of word interactions. The study shows that such graphs exhibit two key features: the small-world effect and a scale-free distribution of degrees. The small-world effect refers to the short average distance between words, which is around 2-3, despite the large number of words that can be stored in the human brain. The scale-free distribution indicates that some words are highly connected, and their removal can significantly affect the network. The graph of human language shares properties with other complex systems, such as biological and technological networks. These properties suggest that language has an evolutionary and social history that influences its structure and flexibility. The study also shows that the distribution of word frequencies follows a power law, indicating that the most common words are highly connected and play a crucial role in language. This scale-free structure allows for efficient communication and flexibility in sentence construction. The research also explores the implications of these properties for language disorders. The removal of highly connected words, such as function words, can lead to communication difficulties, as seen in conditions like agrammatism. The study highlights the importance of these highly connected words in maintaining the structure and function of language. Overall, the findings suggest that the organization of language is a complex system with properties that reflect its evolutionary and social origins.