Know is either saber or conocer. Sabermeans to know a fact or piece of information, conocer means to be familiar or acquainted with.
With saber
I know -> yo sé
You know -> tú sabes (familiar)
You/he/she knows -> Usted/él/ella sabe
They know -> Ustedes/ellas/ellos saben
We know -> nosotros sabemos
With conocer
I know -> yo conozco
You know -> tú conoces (familiar)
You/he/she knows -> Usted/él/ella conoce
They know -> Ustedes/ellas/ellos conocen
We know -> nosotros conocemos
This is how u say it in spanish: que quieres saber?
Translation: Sabes español?
¿Sábes qué? = Do you know what?
¿Me conoces?
i didn't know that you speak spanish = no sabía que hablas español.
Yeah, I do...lol did you mean, How do you say, you know lots of Spanish? If that's the case, then you say,"Sabes mucho español".
Do you know about that is: Sabes de eso
how to say,you must know your child's weight or age in spanish.
No sé
Sabe usted.....
Ellos saben.
" Sabes que"