@lupyuen Never had the chance of meeting Riau Indonesian, but in general Sumateran dialects are language of its own, despite the label of 'Malay dialects'.

But interesting!

'ayam makan' in Indonesian generally means 'a chicken is eating'. Tense can be marked with already, 'ayam sudah makan', 'a chicken is done eating' or 'a chicken has ate'.

'Makan ayam' instead is used for 'eating chicken' in Indonesian.

Makan apa? (What are you eating?)
Makan ayam. (I'm eating chicken.)