Nakaka-intindi po ba kayo ng Tagalog? Nakaka-intindi = can understand po = an honorific particle kayo = you (plural); also used as a substitute for "ikaw/ka (you, singular)" in formal conversations I hope this helps! Kuon o inorimasu! :D

or... "Nauunawaan po ba n'yo ang Tagalog?" (just edited) "Naiintindihan n'yo po ba ang Tagalog?" :)