Pronunciation: [wˌɒt hˈɪʃə nˈe͡ɪm] (IPA) 
The phrase "what hisher name" is incorrect as it merges "his" and "her" together, creating a non-existent word. The correct phrase is "what's his/her name". The contraction "what's" combines "what" and "is" while a slash is used to differentiate between "his" and "her". The correct pronunciation for this phrase would be /wʌts ˈhɪz ər ˈneɪm/ or /wʌts ˈhɜr ˈneɪm/ depending on whether "his" or "her" is used.
The phrase "what his/her name" is an interrogative phrase typically used when someone wants to inquire about the identity or designation of a specific person whose name they cannot recall or do not know. It is often utilized to seek information about someone who has been mentioned or referred to but whose name has been forgotten.
The expression "what his/her name" can refer to a specific individual or a group of individuals, depending on the context of the conversation. It is commonly employed to request clarification or to fill in a gap in one's memory regarding the names of people known or encountered.
The phrase is formed by combining the pronoun "what" with the possessive pronoun "his" or "her" and the noun "name." It is typically used in singular form when asking about one person in particular, but it can also be used in plural form when inquiring about multiple individuals.
Overall, "what his/her name" serves as a verbal prompt to indicate the desire for the listener to provide the forgotten or unknown name of the person being referred to. It is an effective and concise way to communicate the need for information about someone's identity without explicitly admitting that one does not remember or know their name.
