v1.5.0 API.AI - Protocol change
This release introduces small but breaking change in protocol model.
Now Fulfillment field from API.AI console becomes composite field in the protocol. Earlier it was simple string field named "speech".
So, "speech" field now in the Fulfillment object. And you should change
response.getResult().getSpeech()
to
response.getResult().getFulfillment().getSpeech()