The abstract concept of ‘like’ and ‘don’t like’ can be difficult for children with autism to understand. Therefore, the concept of ‘like’ and ‘don’t like’ often needs to be taught explicitly, and an effective way (from my experience) to do this is by modelling the language at the exact time the child is either clearly liking or disliking something.
Model language: for example “Steph likes tomatoes” or “Steph doesn’t like the swing”
Verbal language can be reinforced and emphasised using sign and symbol. A warm mention of The Garden School in Hackney where we put ‘like’ and ‘don’t like’ symbols on lolly sticks which makes a great easily accessible resource! One side has ‘like’ on and the other side has ‘don’t like’ on, therefore making it quick and easy to change as required.
In my classroom I would have a pouch on the side of my cupboard which was easily accessible to me at any time, so in the right moment (it can happen anytime!) I could quickly grab the ‘like/ don’t like lolly stick’ and show it to the child whilst they are obviously enjoying/ disliking something.
If the child is verbal, they are likely to repeat the language. I have even had a child get up from her table and walk to the pouch to take the lolly stick and tell me she did not like something, brilliant! She then began using the language ‘like’ and ‘don’t like’ independently herself.