-in

The -in object focus (Patient Focus) is essential for natural Filipino. While object focus is the primary and most natural way to speak when the object is specific, the -in affix is specifically used for 'patient' objects—things that are fully affected, consumed, or moved toward the actor. It is just one of three main object focus affixes.

1. Conjugation Rules:
The affix -in changes its position based on the aspect:

• Neutral: It is a suffix. If the root ends in a vowel without a glottal stop, it becomes -hin (e.g., basa → basahin). The 'h' is an inserted consonant to separate the two vowels. If it ends in a consonant or a vowel with a glottal stop (which already separates the vowels), it takes the plain -in (e.g., sira → sirain). The neutral form is also commonly used for imperative commands.
• Completed: The suffix disappears and is replaced by the infix -in- for consonant-initial roots (e.g., b-in-asa), or the prefix in- for vowel-initial roots (e.g., in-alis).
• Progressive: Requires both the infix -in- (or prefix in-) and reduplication of the first syllable (e.g., b-in-a-basa, in-a-alis).
• Contemplated: Requires reduplication of the first syllable plus the suffix -in/-hin (e.g., ba-basahin).

2. The Actor Shift:
A critical change when using -in verbs is that the actor (the doer) moves to the ng case. Instead of saying ako (I), you use ko (by me). For example: Babasahin ko ang libro (I will read the book, lit. The book will be read by me).

3. Phonological Changes & Irregularities:

• Syncope (Vowel Dropping): Some roots drop their final vowel when the suffix is added (e.g., bili + -in becomes the verb bilhin. Note that bilihin is incorrect as a verb, but is a valid noun meaning 'goods to buy' or 'prices').
• d to r: The letter 'd' typically changes to 'r' when the suffix -in is added because the 'd' becomes trapped between two vowels (e.g., lakad → lakarin).
• o to u: When a root ends in 'o', it changes to 'u' before adding the suffix (e.g., luto + -in → lutuin).
• Metathesis: For roots starting with l, r, w, or y, the infix -in- mandatorily swaps places to become the prefix ni- (e.g., luto becomes niluto instead of linuto, and yapos becomes niyapos).
• Irregular Roots: The highly common verb kuha (to get/take) irregularly becomes kunin.

Note: Not all objects take -in. Depending on the verb, the object focus might require -an or i- instead.