At what age do children typically narrow their utterances to sounds relevant in their language?

Children typically narrow their utterances to sounds relevant in their language around the age of 1 year. This process occurs as they begin to recognize and differentiate sounds that are significant in their native language, a phenomenon known as phonetic tuning. Prior to this stage, infants babble and produce a wide variety of sounds, including those that may not be present in their language. However, as they approach their first birthday, they start to focus more on the phonemes and patterns that are part of the language they are exposed to in their environment. This stage is crucial as it lays the foundation for effective communication and language development, setting the stage for more complex speech and language skills as they grow.