Actor Focus: '-um-' and 'mag-'

01

'-um-' Is an Infix

-um- does not sit in front of the root — it burrows inside it, landing immediately before the first vowel. This is why the resulting verbs can look so unlike their roots at first.

• kain → kumain (to eat)
• bili → bumili (to buy)
• takbo → tumakbo (to run)
• punta → pumunta (to go)

When the root begins with a vowel, there is no consonant to slip behind, so um- simply goes in front: alis → umalis, inom → uminom, upo → umupo.

• Bumili ako ng isang dosenang itlog.

  I bought a dozen eggs.

• Kailangan ko nang umalis.

  I have to go now.

• Mangyaring pumunta ka sa tindahan.

  Please go to the store.

02

'mag-' Is a Prefix

Mag- is far easier to spot: it simply attaches to the front, leaving the root intact.

• luto → magluto (to cook)
• trabaho → magtrabaho (to work)
• aral → mag-aral (to study)

• Nagbabasa kami ng libro.

  We are reading a book.

• Gusto kong mag-bake ng cake.

  I want to bake a cake.

Note the hyphen in mag-aral, mag-usap, mag-order: it is written whenever the root starts with a vowel, and also before borrowed words.

03

Which One Does a Root Take?

There is no reliable rule, and this is one of the genuine memorisation burdens of Tagalog. Most roots simply pair with one of the two, and you learn them together. That said, some tendencies help:

• -um- often marks an action turned inward — something the doer undergoes or does to or with their own body: umalis (leave), umupo (sit), tumakbo (run), tumaba (gain weight).
• mag- often marks an action turned outward — deliberate, involving tools, objects, or an activity carried on for a while: magluto (cook), maglinis (clean), magtrabaho (work), magmaneho (drive).

04

When One Root Takes Both

A handful of roots accept both affixes, and then the meaning splits — sometimes dramatically. This course teaches one such pair, both built on the root kita:

• kumita — to earn: what you gain comes toward you
• magkita — to meet: two people each go out toward the other

• Sige. Kita tayo bukas.

  Fine. See you tomorrow.

The textbooks' favourite pair works on the same logic — bumili is "to buy", the goods coming toward you, and magbili is "to sell", sending them away. You will rarely meet that second word in modern speech, so learn bumili as a word in its own right rather than as half of a set.