The word "哭喊" is formed by combining the character "哭", meaning to cry, which incorporates the mouth radical "口" to indicate vocalization, with the character "喊", meaning to shout, which also uses the mouth radical "口" and includes the component "咸" for phonetic and semantic contributions related to sound. This combination creates a compound word where both characters contribute their individual meanings of vocal distress, resulting in the combined sense of crying out loudly.