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 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. Contributing to closing this gap, we have systematically classified and analyzed research papers 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：作为一种理解、生成和处理自然语言文本的高效方法，自然语言处理（NLP）研究近年来呈现出迅猛发展态势与广泛应用。尽管该领域研究日益增多，学界已对若干NLP相关方法进行了综述，但尚未出现能够系统归类既有课题、识别发展趋势并勾勒未来研究方向的全景式研究。为填补这一空白，我们系统性地对ACL文集中的研究论文进行了分类与分析。由此，我们呈现了该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，并指明了未来工作的方向。