Accepting
Boleh. ‘Sure.’
Ayo. ‘Let’s.’
Mau. ‘I’d like to.’
Ikut! ‘I’m in.’
One word each. Enthusiasm is shown by tone rather than by adding words.
Declining, the shape of it
A bare tidak is understood and lands badly. The expected form has three parts: an apology, a reason, and a door left open.
Maaf, aku ada acara. Lain kali ya. ‘Sorry, I’ve got something on. Another time.’
Maaf is the apology. Ada acara ‘I have something on’ is the reason, and it is deliberately vague, which is fine and expected. Lain kali keeps the relationship going.
Leaving out the third part is what makes a refusal sting.
The reasons people actually give
Ada acara. ‘I’ve got something on.’
Lagi capek. ‘I’m tired.’
Nggak enak badan. ‘I’m not feeling well.’
Belum tentu bisa. ‘I’m not sure I can.’
Nobody expects detail. Offering a full explanation is more foreign than offering none.
Sayangnya
Sayangnya ‘unfortunately’ softens a refusal in a more formal setting.
Sayangnya saya tidak bisa. ‘Unfortunately I can’t.’
Note sayang again, in its “what a shame” meaning from the A1 affection lesson rather than its “love” one.
Nggak enak
Nggak enak literally means “not tasty” and socially means awkward, uncomfortable, reluctant to impose. It has no English equivalent and it explains a great deal of behaviour.
Aku nggak enak minta tolong. ‘I feel awkward asking for help.’
Nggak enak sama dia. ‘I’d feel bad towards him.’
This feeling drives refusals, over-politeness, and the reluctance to give a direct no that you met in A1. Recognising the phrase tells you what is really going on in a conversation.
And the soft no you receive
From A1: nanti, mungkin, belum tentu, insya Allah. Applied to invitations, these mean no more often than they mean maybe. The tell is the absence of a counter-proposal.
If someone wants to come, they suggest a different day.