Asking Someone to Speak Slower

You're struggling to keep up with a fast speaker and politely ask them to slow down.

Local
Sí, entonces tiene que caminar dos cuadras y luego girar a la izquierda en la esquina donde está la farmacia.
see, en-TONE-ses TYEH-neh keh kah-mee-NAR dohs KWAH-drahs ee LWEH-go hee-RAR ah lah ees-KYEHR-dah en lah ehs-KEE-nah DOHN-deh ehs-TAH lah far-MAH-syah
Yes, so you have to walk two blocks and then turn left at the corner where the pharmacy is.
This is deliberately fast and long — exactly the kind of response that overwhelms beginners.
You
Perdón, no entiendo. ¿Puede hablar más despacio, por favor?
pehr-DOHN, noh ehn-TYEHN-doh. PWEH-deh ah-BLAR mahs dehs-PAH-syoh, por fah-VOR?
Sorry, I don't understand. Can you speak more slowly, please?
'Más despacio' literally means 'more slowly' and is the most common way to ask someone to slow down.
Local
Claro. Caminar... dos cuadras... y girar a la izquierda.
KLAH-roh. kah-mee-NAR... dohs KWAH-drahs... ee hee-RAR ah lah ees-KYEHR-dah.
Of course. Walk... two blocks... and turn left.
You
Ahora sí entiendo. ¡Muchas gracias!
ah-OH-rah see ehn-TYEHN-doh. MOO-chahs GRAH-syahs!
Now I do understand. Thank you very much!
'Ahora sí' is a useful expression meaning 'now yes' — used when something finally clicks.