Malay cuisine is the most difficult to identify. The mixtures of Chinese, Indian and Indonesian influences are profound. Some aspects are easily worked out since the majority of Malay people are Muslim so pork rules out the probability of a Malay recipe. Nazlina Hussin the writer of Pickles and Spices World blog has helped me on some pointers and things like turmeric leaves aren't used in Indian or Chinese cuisine. Separating Indonesian and Malay is more of a local experts field as the names give the origin away.
What is Malay? Malay people are the original or longest dwelling peoples of the Malay peninsula. Their origins are diverse and are a group of tribal like migrants from various places who established their living in this part of the world. Malay is also the name given to the official language of Malaysia. Malay are one of the groups who make up the citizens of Malaysia the others being of Indian and Chinese descent. Malaysia is consequently a real multi-cultural society with currently a noticeable atmosphere of increasing cohesiveness. There was a period post independence where there was a noticeable feeling of Malay priority and privilege with resentment by the Chinese and Indian citizens. This has certainly normalised in the post Dr Mahatir period.
I'm sure I will make errors in classification of the foods particularly assigned to Malay cuisine and I apologise for these oversights in advance. My purpose in separating these is not to show one against the other in any way or even to say that I enjoy a specific Malaysian cuisine over another. The purpose is to attribute and understand the cuisine as a culture of the Malay peoples and even going back to earlier generations. Of course it's always interesting to see differences in regions of the one cuisine and I am not sure I will be able to do this. My knowledge is very limited on Malay cuisine and evolution.
Another aspect of all of this is that the Malay cuisine is rich. It is poorly known outside Malaysia and is probably under some threat because of the domination of the Indian, Nyonyah and Chinese cuisines. It's not a competition but if it's swamped by other cuisines within the one country then it will decline. Food is part of culture as is language and it's important to know the cuisine if we value the culture. Not many of us will learn the language but we can familiarise ourselves with what is Malay and enjoy it as Malay food.