First step in child language development is:

Language development in children follows a natural progression, starting from simple sounds and evolving into complex speech patterns. This process begins at an early age, as children gradually learn to recognize, understand, and produce words. 

Key Points

•  In the early stages of language development, children typically start by learning nouns.
• Nouns are concrete and refer to familiar objects, people, and things in their environment, such as "mama," "ball," or "dog."
• Since nouns represent tangible entities, they are easier for children to associate with real-world experiences.
• This stage is crucial because it lays the foundation for vocabulary expansion and further language skills. 

Thus, it is concluded that First step in child language development is noun.

Hint

•  Pronouns, such as "he," "she," and "it," are acquired later when children start forming sentences.
• Verbs, which indicate actions, follow nouns as children begin to describe activities.
• Tenses, which involve a more advanced understanding of grammar and time, develop much later when children start structuring sentences correctly.