When do we use the verbs with PREFIX and without PREFIX

Actually, as an Indonesian myself, I couldn't explain this rule for you. Indonesian suffix is pretty complicated itself so the best advice I could give you is the trial-and-error method

ajar, minum dan beri itu kata dasar. Pengunaan imbuhan itu untuk membentuk kata kerja, banyak sekali bentuk imbuhan tergantung dari bentuk kata dasar itu sendiri.

Here's an additional note.

In Bahasa Indonesia, you can use either "infinitive" (minum; beri) or combination "me-infinitive" (meminum;memberi) for active expressions. Therefore, both are acceptable.

While;
S + me-inf. (+ O + Compl.) , is most used in written expressions.
S + inf. (+ O + Compl.) , is more suitable in narrative expression (literary/writing) or within conversation.

In contrary, for passive expressions, you can use prefix "di-infinitive" (diminum;diberi) or "ter-infinitive" (terminum).

Hopefully, these would answer your curiosity..

"Ajar" and "belajar" have their own meanings, those are different words.

Saya ajar :  I teach

Saya belajar : I learn

 

Same as in English for : Subject + Verb

Saya minum : I drink

saya beri : I give

 

Same as in English for : Subject + Verb+ing, but in Bahasa Indonesia : Subject + Me / Mem / Meng + Verb

Saya meminum : I am drinking

saya memberi : I am giving

The word without "imbuhan/verb" can be use while saying something for future tense, example :

- Saya akan ajar kamu cara menjahitnya.

- Saya akan minum air itu nanti.

 

Hi There...

i'll try to answer your question.

1. Saya ajar atau saya belajar

I guess the word 'ajar' can't use alone. it must add with, we say here, 'imbuhan'.

ex: saya (be-l-)ajar > > > > I study          /      Saya (me-ng-)ajar > > > > I teach

 

2. Saya minum autau saya meminum

3. Saya beri atau saya memberi

For those sentences, I guess the difference is just between Formal  or Informal usage...The meaning is same

 

Formal/standard                                   Informal

Saya meminum                       saya minum

Saya memberi                                                saya beri

 

I hope my explanation is clear to you.. I'm sorry for any mistake ^___^