(IJACSA) International Journal of Advanced Computer Science and Applications, Vol. 12, No. 9, 2021 291 | Page www.ijacsa.thesai.org Recent Progress, Emerging Techniques, and Future Research Prospects of Bangla Machine Translation: A Systematic Review M. A. H. Akhand 1 , Arna Roy 2 , Argha Chandra Dhar 3 , Md Abdus Samad Kamal 4 * Dept. of Computer Science and Engineering, Khulna University of Engineering & Technology Khulna-9203, Bangladesh 1, 2, 3 Graduate School of Science and Technology, Gunma University, Kiryu 376-8515, Japan 4 Abstract—Machine Translation (MT), the way of translating texts or documents from a source language to a target language automatically without human intervention, has gained popularity in the growing information technology-based era of globalization. Bangla is a major language, and several MT studies with different tools and techniques have been investigated in the last two decades. Considering the importance of the Bangla language and its prospects in MT studies, this study provides a comprehensive review of existing Bangla MT studies to meet the timely demand. Specifically, at first, the basic ideas of different MT methods (Rule-based, Example-based, Statistical, Neural, and Hybrid) and performance measures of MT are presented as a background study of the present review. Then an overview of the Bangla language and a brief description of the available Bangla-English corpora are provided. Next, a description of the existing Bangla MT studies is provided categorically following the common strategic fashion to create a valuable reference for current researchers in the field that is also suitable for non- expert users. The achieved performances of individual methods are also compared in a tabular form. Finally, a number of future research prospects are revealed from the studies, encouraging researchers and practitioners to develop a better and comprehensive Bangla MT system. Keywords—Machine Translation (MT); Bangla language; rule- based MT; example-based MT; statistical MT; neural MT; hybrid MT I. INTRODUCTION The task of content (e.g., voice, speech, texts) translation from one natural language to another has become indispensable in politics, business, research, and other areas, and a human expert usually handles such tasks. Human translators perform a masterful job interpreting conversations between two or more persons (e.g., country chiefs, tourists, business giants) who speak in different languages. Due to rapid globalization, translation becomes essential for ordinary people; translation of web content (e.g., website, document) is also necessary for the era of digitalization and the internet. To handle the translation of such huge contents (especially text, document, and web), machine translation (MT) is a promising research area [1]. In general, MT refers to translating texts or documents from the source language (SL) into the target language (TL) without human intervention. Individual natural languages advocacy inherently dominated respective MT studies as resources (e.g., corpus) and language-dependent efforts. Specifically, corpus, rules, and other resources of a particular language pair (e.g., English-German) are not usable in MT for another language pair. Moreover, the MT system developed for a particular language pair is not appropriate for other cases as an individual language holds distinct grammar and phrase rules. As the most internationally used language, MT researches are mainly English language concentric. High resource availability and major MT studies with remarkable performance are available for English-French [2], English- German [3], English-Chinese [4] language pairs. Thousands of other natural languages, including several major languages, are remained much behind in MT activities. Specifically, Bangla is one of the most broadly spoken languages, with approximately 228 million native speakers (fifth-most) and 37 million second-language speakers (seventh-most) [5]. However, MT resources and studies are limited for Bangla. Several Bangla-English MT studies are available with different methods, but their achievements are not significant compared to the resource-rich language [6]–[8]. Therefore, it is a timely demand to line up existing Bangla MT studies for the researchers who intend to work in this promising research field and find a motivation to enhance Bangla MT. This study is a comprehensive review of Bangla MT studies focusing on individual methods and techniques employed, corpus and/or resources used, and performance achieved. As a prerequisite, the fundamentals of various MT methods, the significance of the Bangla language, and MT performance measurements are explained briefly in Section II. Benchmark corpora and resources for Bangla MT; and individual Bangla MT studies are summarized under different MT categories in Section III. The significance of the current review study and prospects of Bangla MT studies are discussed in Section IV and Section V, respectively. Finally, Section VI briefly concludes the present study with few remarks. II. BACKGROUND Various techniques and tools were developed in the last few decades through remarkable research efforts for appropriate MT outcomes in different languages. At the basic level, MT executes the translation of atomic words from one language to another using a dictionary. Nowadays, it is possible to translate whole sentences through corpus techniques, rule-based grammatical techniques, or even idioms *Corresponding Author