"Aprender" is the Spanish verb meaning "to learn". The first person present conjugation is "aprendo". The personal pronoun "I" (yo in Spanish) is not normally used. So...the phrase "I learn Spanish" is expressed as "aprendo español".
You would say "Yo quiero aprender español" or if you wanted to say I want to know spanish you would say "Yo quiero saber español". It is optional to leave out the "yo" and just say "Quiero aprender...