ter- (kemampuan)

The ter- prefix has several functions, but the 'abilitative' or 'potential' function is one of the most common in daily life. It replaces the meN- or di- prefixes to shift the focus to possibility. Because it functions as a passive voice, this construction is strictly used with transitive verbs (verbs that take an object).

1. Passive Structure and Pronoun Placement:
Crucially, the potential ter- functions as a passive construction. This means the thing being acted upon is the subject. You cannot use an active structure like "Saya tidak terbaca buku". Furthermore, unlike some passive forms, you cannot place the agent pronoun before the verb. "Buku itu tidak saya terbaca" is incorrect; use a following oleh phrase, as in "Buku itu tidak terbaca oleh saya" (That book is not readable by me).

2. Negative and Positive Constructions:
Potential ter- often occurs in negative constructions with tidak (not) or belum (not yet). It often expresses that an action is impossible to complete due to lack of ability, resources, or time (e.g., tidak terbeli meaning 'unaffordable'). Positive perception expressions such as terlihat jelas (clearly visible) are also ordinary; the distribution depends on the particular verb.

3. Potential vs. Resulting State and Accidental Action:
The potential meaning (e.g., terbaca meaning "legible" or "can be read") is common. However, ter- can also indicate a resulting state (e.g., terbuka meaning "is open") or an accidental action (e.g., terinjak meaning "accidentally stepped on"). These are distinct functions of the same prefix; context usually clarifies if you are describing an ability, a current state, or an involuntary event.

4. Suffix Retention:
When a verb that usually takes the -kan or -i suffix is used in this potential sense, the suffix is regularly retained in standard formal Indonesian. For example, memecahkan (to solve) becomes terpecahkan (can be solved), and mengatasi (to overcome) becomes teratasi (can be overcome). Dropping -kan or -i changes the word's meaning rather than preserving the potential meaning. An everyday alternative is bisa di- or nggak bisa di- ; this does not make ordinary forms such as terlihat unsuitable for conversation.

5. Key Meanings:

• Perception: Used for things that can be sensed, like terlihat (visible) or terdengar (audible).
• Affordability/Capacity: Used for things that can be bought or reached, like terbeli (affordable) or terjangkau (reachable).
• Legibility: Used for information that can be processed, like terbaca (legible).

6. Phonological Rules:

• If the root starts with 'r', the 'r' in ter- is dropped: ter- + rasa → terasa (can be felt).
• If the first syllable contains 'er', the 'r' is often dropped: ter- + percaya → tepercaya (trustworthy).

7. Agent Marking:
To mention who is (or isn't) able to do the action, use oleh (by). While oleh is the standard marker for learners, it can be omitted if the agent follows the verb directly (e.g., tidak terbaca saya). Furthermore, the agent is very frequently omitted entirely when the statement applies generally to anyone (e.g., Suaranya tidak terdengar meaning 'His voice cannot be heard [by anyone]').

8. Everyday Alternatives:
In daily spoken Indonesian, it is highly common to substitute the abilitative ter- with bisa or dapat combined with a di- passive verb. For example, instead of tidak terbaca, people frequently say tidak bisa dibaca (cannot be read).