The small script witch extract conversation from json file
You need download skype history from official skype website. This is instruction for this : https://support.skype.com/en/faq/FA34894/how-do-i-export-my-skype-files-and-chat-history
After downloading, you need to know the id of conversation. You can open the json history and find that id. Ok now you can extract these messages:
python3 conversation.py messages.json 19:[email protected] output.json