Learn Spanish (Spain): ¿Cuál es tu apellido?

In Spanish, when asking for specific personal information like a name, surname, or phone number, we use ¿Cuál es...? (which literally means "Which is...?"). If you use ¿Qué es...?, you are asking for a dictionary definition. So, ¿Qué es tu apellido? would sound like you are asking "What is the dictionary definition of your surname?"

Why doesn't tu have an accent mark here?

The word tu without an accent mark means "your", which shows possession of the surname. If it had an accent mark (tú), it would mean the subject pronoun "you". This is a handy way to tell them apart in writing!

How do I pronounce the double "L" in apellido?

In Spain, the double "L" (ll) is usually pronounced like the English "y" sound, similar to the "y" in "yellow". So, the ending of apellido sounds like "yee-doh".

If apellido means "surname", how would I ask for someone's first name instead?

To ask for a first name, you use the word nombre. You can keep the exact same sentence structure and just swap the last word: ¿Cuál es tu nombre?