Can somebody tell me how to dynamically add utterances to the simple utterances list and intent slots in Alexa skill from lambda function? Or is there another method of recognizing raw text because I can't predefine utterances since I only get the certain names in the moment of executing Lambda function.
Bad news, there's currently no API to dynamically add utterances and intents and slots. All updates are through the UI and when your intent, utterance and slot lists grow that update can sometimes take a while.
You might make liberal use of custom slots and see what happens. I just read (scroll down to blue section) that custom slots may return slot data back that may not be in the predefined list. I wonder if it's context aware, in that it will return like data for a particular slot depending on the values defined for that slot. It would be worth trying. For example...
someIntent how many {FRUIT_LIST} will a {ANIMAL_LIST} eat
FRUIT_LIST oranges, apples
ANIMAL_LIST dog, cat
"How many carrots will a horse eat?"