## 2 Related Work
### Usability of CAT  
According to ISO [14; 15], usability can be defined as \"the capability of a software product to be understood, learnt, used, and that is attractive to the user when used in specified conditions.\" It is considered as a key factor in software development and design. Usability involves three distinct attributes: (1) Effectiveness, i.e., the accuracy and completeness with which users achieve certain goals; (2) efficiency, i.e., the link between the accuracy and completeness with which users achieve certain goals and the resources expended in achieving them; and (3) satisfaction, i.e., the users' comfort with and positive attitudes toward the use of the software [16]. Few studies examined the usability of some CAT tools [3; 5; 17; 18; 19]. These studies focused on the advantages and disadvantages of CAT tools from the translators' perspectives that aimed at encouraging user-centered software design that takes into account user needs. In Lagoudaki [3], 874 professional translators were asked to evaluate the advantages and disadvantages of translation memory systems. Several needs related to the functionality of these systems were identified, such as resource building, project management and quality control, search and translation assembly capabilities, and the facilitation of collaboration. The study revealed that usability and the needs of end-users are usually overlooked during the design and development of TM systems. The researcher suggests that software developers must make sure they address expected requirements, performance requirements, as well as existing requirements to satisfy users' needs. An ethnographic study by [PERSON] [17] examined the perceptions of translators on CAT tool usability at a translation agency. Fourteen professional translators who worked in different organizational settings were observed and interviewed. The study revealed that although the translators expressed positive attitudes toward the translation technology, they also expressed some dissatisfaction with regard to the user interfaces, complicated features, and the lack of flexibility in these tools. These factors can impact the translation workflow and cause frustration. The findings show that there is a strong need for the optimization of translator workplaces and for the improvement of current translation environment tools. Another ethnographic study was conducted by [PERSON] [18] in three translation firms in Canada that focused on the advantages and disadvantages of TMs when used at the workplace. Interviews and shadowing techniques were used to collect data on the translator perceptions of technology-enhanced working environments. The study found that most of the participants agreed that CAT tools enhanced the translation consistency and reduced repetitive work. However, their dissatisfaction revolved around the tool's conception or design. [PERSON] [5] conducted a usability study to assess the students' perception of SDL Trados Studio (SDL plc, Berkshire, UK), an extensively used desktop CAT software. The researcher asked 95 translation students to evaluate the efficiency, affect, usefulness, control, and learnability attributes of the software with the use of the SUMI questionnaire. Results showed that student opinions about the global usability of the software were within the average range, unlike its learnability that was below the average range. The only scale above average was that related to attribute affect. The researcher concluded that more emphasis is needed on the design of this CAT tool to adapt to the real needs of the translators. In the context of Arab translators, [PERSON] [13] conducted a study to examine translator perceptions of CAT tools and explore the challenges that can hinder the use of these tools. The researcher used an online survey and conducted an observational experiment with 49 translators. Results revealed a strong inclination by Arab translators to encourage and support the use of CAT tools despite the challenges.