This book constitutes extended, revised, and selected papers from the 12^th International Symposium on Artificial Intelligence supported by the Japanese Society for Artificial Intelligence, JSAI-isAI 2020. Organized in the Tokyo Institute of Technology, it was held virtually due to COVID-19 pandemic.
The 19 full papers were carefully selected from 50 submissions and present two workshops: Logic and Engineering of Natural Language Semantics (LENLS 2020) focus on the formal and theoretical aspects of natural language. It is an annual International Workshop recognized internationally in the formal syntax-semantics-pragmatics community. The 14^th International Workshop on Juris-informatics (JURISIN 2020) details legal issues for the perspective of information science. This workshop covers a wide range of topics, including any theories and technologies which are not directly related with juris-informatics but have a potential to contribute to this domain.

LENLS Logic and Engineering of Natural Language Semantics (LENLS) .- A Semantics for "Typically" in First-Order Default Reasoning.- On dialogue modeling: a dynamic epistemic inquisitive approach.- Knowledge acquisition from natural language with Treebank Semantics and Flora.- The Explicated Addressee: A (mainly) pragmatic account of Japanese ka-questions.- Superlative Modifiers as Concessive Conditionals.- Polynomial Event Semantics: Negation.- Oleg Kiselyov Experiential Imagination and the Inside/Outside-Distinction.- Against the multidimensional approach to honorific meaning: A solution to the binding problem of conventional implicature.- A Persona-based Analysis of Politeness in Japanese and Spanish.- JURISIN2020 Fourteenth International Workshop on Juris-informatics (JURISIN 2020) .- AI and Judicial Policy.- Differential Translation for Partially Amended Japanese Statutory Sentences.- Aspect Classification for Legal Depositions.- COLIEE 2020: Methods for Legal Document Retrieval and Entailment.- COLIEE 2020: Legal Information Retrieval & Entailment with Legal Embeddings and Boosting.- BERT-Based Ensemble Model for Statute Law Retrieval and Legal Information Entailment.- Chuen Huang The Application of Text Entailment Techniques in COLIEE 2020.- Information Extraction / Entailment of Common Law & Civil Code.- Paragraph Similarity Scoring and Fine-Tuned BERT for Legal Information Retrieval and Entailment.- Using BERT and TF-IDF to Predict Entailment in Law-Based Queries.