Question: when do you use ng an when do you use na

BASE form...ANG always marks the FOCUS verbNG usually marks the non-focus / secondary verbisang is often used after the SA prepositional marker rather than repeat NGNA is an ADJECTIVE MARKER/CONNECTER/LIGATURE before or after a COMMON NOUN ( any noun other than pronouns or proper names). The adjective is TIED to the noun so rather than "dangle" the adjective is super clear what noun is modified.So...eitherANG adjective NA focus noun (or post-position ANG focus noun NA adjective) or NG adjective NA non-focus noun (or post-position NG non-focus noun NA adjective) And of course...NA switches to -ng for adjectives ending in a vowel or -g for adjectives ending in N.And could be more details...depende depende...palagi...To my ear...Filipino is classic Tertris...Jurassic naman! Few ideas clarrified and smoothed to the ear by connectors throughout. Just connect all the parts if you can hang...Super Astig. Rapsa Toinkers!

We use -ng and na to connect adjectives to nouns.'-ng' is attached to an adjective ending in vowels and the letter 'n'.
mabuti + tao = mabuting tao (a kind person)
mainhin + babae = mainhing babae (a demure woman)'na' is used after an adjective ending in consonants (except for 'n')maingay + kalsada = maingay na kalsada (a noisy street)There are other usages too. But I hope this helps!