Hello. Both mean the same but the second one it´s formal. ¡Buena suerte con su español! (if you were in Mexico, you´d be telling this to your boss, someone you just met, someone you have a lot of respect or someone really old) Saludos Edgar

Hello Haley, ¡Buena suerte con tu español! ¡Buena suerte con su español! Both sentence are similar but the first one is informal (tu) and the second one is more formal (su). In Spanish we have the next one posesive articles: mi español tu español su español nuestro español vuestro español su español (sería este de aquí) I believe that could one answer. I hope that I could help you! Miguel

Both sentences are correct. TU is used when talking to your friends and family. SU is used when you are talking to someone who you just met or someone you are talking to in a formal or professional setting. So TU is informal and SU is formal. Hope this helps. ¡Buena suerte con su español!

it means the same, the difference is just tu and su ... tu is more informal and su more formal

the 02 sentences say exactly the same, but one is formal and the other informal. for example: ¡Buena suerte con tu español! (informal) with friends ¡Buena suerte con su español! (formal) unknown Good luck with your Spanish ;)