Introduction
If my memory serves me right, we first covered this back when I was in 4th grade. I find it essential to post this particular subject publicly after realising the confusion that learners are facing with the scarcity of Filipino grammar books in English online. Hope this thing would help and encourage you more in learning Tagalog. Good luck! :)
Trigger System vs. Voice System
First we have to understand that Filipino languages in general follow the "trigger system" opposed to the English "voice system". The voice system emphasises either the agent or the patient, with the trigger system we distinguish more - the direction, the beneficiary, the location, etc. In the voice system, the voice dictates the focus whereas in the trigger system, especially in Tagalog, it's the various triggers in form of verb affixes.
Mga Pokus ng Pandiwa (in no particular order)
a) Tagaganap (Actor-Focused)
<em>Kumuha ako ng pera mula sa aparador.</em>
<em>I took money from the cabinet.</em>
* Use direct pronouns (ako, ka, kayo, siya, tayo, sila)
<em>Present form: Kumukuha</em>
<em>Future form: Kukuha</em>
b) Layon (Object-Focused)
<em>Kinuha ko ang pera mula sa aparador.</em>
<em>I took some money from the cabinet.</em>
<em>Present form: Kinukuha</em>
<em>Future form: Kukuhanin/kukunin</em>
c) Tagatanggap (Beneficiary-Focused)
<em>Ipinagkuha na kita ng pera mula sa aparador.</em>
<em>I already took some money for you from the cabinet.</em>
<em>Present form: Ipinagkukuha</em>
<em>Future form: Ipagkukuha</em>
d) Gamit (Instrumental-Focused)
<em>Ipinangkuha ko ng mga lirato ang aking cellphone.</em>
<em>*Translit.: used to (I) take pictures my cellphone.</em>
<em>I used my cellphone to take pictures.</em>
<em>Present form: Ipinangkukuha</em>
<em>Future form: Ipangkukuha</em>
<em> </em>
e) Direksyon (Direction-Focused)
<em>Kinuhanan ko ng pera ang aparador.</em>
<em>*Translit.: Took from (I) money the cabinet.</em>
<em>I took money from the cabinet.</em>
<em>Present form: Kinukuhanan</em>
<em>Future form: Kukuhanan</em>
f) Ganapan (Location-Focused)
<em>Si Juan ang pinagkuhanan ko ng pera.</em>
<em>John is whom I got the money from.</em>
<em>Present form: Pinagkukuhanan</em>
<em>Future form: Pagkukuhanan</em>
g) Sanhi (Cause-Focused)
<em>Nahuli akong natutulog sa trabaho, na ikinakuha ko ng warning memo.</em>
<em>I was caught sleeping at work, which caused me to get a warning memo.</em>
<em>Present form: Ikinakukuha</em>
<em>Future form: Ikakukuha</em>
h) Resiprokal (Reciprocal)
* the act is done by the subjects simultaneously on each other making them objects too at the same time.
<em>Nagkuhanan sila ng litrato ng bawat isa.</em>
<em>They took pictures of each other.</em>
<em>-or simply-</em>
<em>Nagkuhanan sila ng litrato.</em>
<em>Present form: Nagkukuhanan</em>
<em>Future form: Magkukuhanan</em>
