The word "嘱咐" is formed by combining two characters, each containing the speech radical 口 (mouth) to indicate relation to verbal communication. The first character, 嘱, uses 口 for meaning and 属 primarily for phonetic value, conveying "to instruct". The second character, 咐, similarly uses 口 for meaning and 付 for sound, meaning "to tell". Together, they create a compound word meaning to give instructions or advice through repeated or emphatic speech.