As an efficient approach to understand, generate, and process natural language texts, research in natural language processing (NLP) has exhibited a rapid spread and wide adoption in recent years. Given the increasing amount of research work in this area, several NLP-related approaches have been surveyed in the research community. However, a comprehensive study that categorizes established topics, identifies trends, and outlines areas for future research remains absent to this day. Contributing to closing this gap, we have systematically classified and analyzed research papers included in the ACL Anthology. As a result, we present a structured overview of the research landscape, provide a taxonomy of fields-of-study in NLP, analyze recent developments in NLP, summarize our findings, and highlight directions for future work.

翻译：作为理解、生成和处理自然语言文本的有效途径，自然语言处理（NLP）研究近年来呈现出快速扩展和广泛应用的趋势。鉴于该领域研究工作的持续增长，学术界已对若干NLP相关方法进行了综述。然而，至今仍缺乏一项能够系统分类现有主题、识别发展趋势并勾勒未来研究方向的综合性研究。为填补这一空白，我们对ACL文集收录的研究论文进行了系统性分类与分析。由此，我们呈现了研究领域的结构化概览，建立了NLP研究领域的分类体系，分析了NLP的最新进展，总结了研究发现，并指出了未来研究方向。