Section 3 of 7
ZINinNGT prototype description
Jos Ritmeester, Beyza Sümer, Marije Boonstra, Maartje de Meulder, Belinda van der Aa, and Floris Roelofsen · about 7 minutes
In this section, we describe our initial design objectives and provide an overview of the prototype’s design and main features. Finally, we map the design objectives onto the prototype’s features to illustrate how the objectives are operationalized.
Design objectives
Based on the literature discussed in Sects. 1 and 2, we identify several design objectives for our parent-facing app.
First, because parents and NGT teachers express the need for sign language materials that move beyond isolated vocabulary [14–16], the app should do so and provide grammar-aware input. This includes NGT sentences ranging from simple (suitable for beginners and parents of very young children) to more complex sentences (for advanced learners and parents of slightly older children). In addition, grammar explanation videos should be included to help parents understand the key grammar constructions in these sentences, as well as to reinforce explanations from their sign language courses.
Second, to accommodate different learning styles and preferences—identified by Jamaldeen, Hewagamage, and Ekanayaka [29] as core design principles—the app should support perceptual control. Features include multiple camera angles, adjustable playback speed, and optional subtitles (at sentence- or word-level).
Third, the app should enable need-driven retrieval. Parents should be able to find what they need when they need it. This design principle aligns with findings reported in an earlier publication, in which parents reported that they valued resources that are quick and easy to access [16]. To meet this need, the app must offer a well-organized interface, an intuitive search function, and a sufficiently broad scope so that parents can easily find sentences relevant to their immediate communicative needs. In line with the personalized-learning principle described by Jamaldeen, Hewagamage, and Ekanayaka [29], the app should also support bookmarking, enabling parents to organize and revisit content based on their individual needs.
Finally, although the literature emphasizes the value of interactive activities and motivational elements [29–31] we chose not to incorporate quizzes or motivational features in this prototype. Hearing parents of DHH children are often highly motivated to learn sign language, drawing their primary reward from successful communication with their child rather than from gamified features. For this reason, we initially prioritized the other design objectives. As shown in the Results and Discussion (Sects. 5 and 6), we later reconsidered this decision.
Although not a design objective, it is important to briefly address the app’s content. Because ZINinNGT targets parents of young children, all app content focuses on parent–child interactions and their daily routines. Zarchy and Geer [11] formulated guidelines for family-centered sign language curricula, in which they repeatedly emphasize the importance of content centered around common daily routines. This ensures that the learning material can be integrated immediately and repeatedly into parents’ daily lives, making language learning most efficient.
Prototype design
The ZINinNGT prototype was created in collaboration with YipYip, a Dutch company specializing in app development. ZINinNGT is suitable for both Android and iOS smartphones. In this section, we highlight the prototype’s main features.
Search bar and filters
The app features a search function, as shown in Fig. 1, which allows users to search for two types of videos: (1) videos of example sentences in NGT and (2) videos explaining NGT grammar concepts.
Fig. 1: Home screen of ZINinNGT
Users can search for videos using the search bar, by selecting search filters, or by combining a search term with filters. The prototype offers different search filters, such as “Favorite”, “Themes” and “Grammar”. The “Favorite” filter allows users to only view videos they have marked as favorites, serving as a bookmark function. The “Themes” filter allows users to search for sentences relevant to a specific semantic theme. Through the “Grammar” filter, users can search for example sentences and grammar explanation videos based on specific grammatical components. For instance, selecting "Time expressions" will retrieve all example sentences including time expressions as well as related grammar explanation videos (as shown in Fig. 2).
Fig. 2: Example use of grammar filter
The main idea behind the search bar and the “Grammar” filter is to help users find signs and grammar concepts learned in NGT classes, providing examples for reinforcement and additional explanation. Learners can thus search for newly acquired vocabulary or grammar and see it used in the context of a sentence.
In addition to the search filters, a “Sort” function is also available to organize search results. Users can, for example, sort the videos by shortest or longest sentences first, based on the number of signs per sentence. This function is implemented to reflect a type of sentence complexity where parents of young children might want to prioritize short sentences, while parents of older children or more proficient signers might want to view longer sentences.
Viewing videos
When the app user selects a desired sentence, a video featuring a DHH signer signing the sentence is shown. Each video is presented in a loop for continuous viewing.
Underneath the video, as shown in Fig. 3, four different tools can be selected:Camera angle: Users can choose between three different camera angles (left, right and center) to view the signer from different perspectives;Pause/Play: This tool allows users to pause and resume the video;Subtitles: Users can select Dutch subtitles, no subtitles, or a literal sign-for-sign translation (as shown in Fig. 3). In the sign-for-sign translation, the sign currently being produced receives highlighting to aid users in identifying individual signs;Playback speed: The video speed can be adjusted between four different settings (0.25 to 1x).
Fig. 3: Example video (The signers featured in the prototype videos provided informed consent for the use of their video data within the context of this user study. New videos were recorded before the app was publicly released. For privacy reasons, Fig. 3 shows a newly recorded video rather than the original video used in this user study.)
In the top right corner of the video, two additional tools are available:Information: Clicking this tool opens a new window displaying additional information about the video, including relevant grammar explanation videos tied to the sentence (as illustrated in Fig. 4);Favorite: Users can mark the video as favorite for easy retrieval.
Fig. 4: Use of the information button
Content
All videos were signed by native DHH signers, who were asked to keep the target group (parents of DHH children aged 1 to 5) in mind to prompt child-directed signing. Their signing was not restricted in any way—for example, they were not requested to use standardized signs or to adhere to basic word order often taught in NGT classes. Although this approach sparked debate among the researchers, it was ultimately decided that the app should reflect the natural variation of NGT as used within the Deaf community.
The current prototype includes 29 example sentence videos to demonstrate the app’s design and functionality. Grammar explanation videos have not yet been integrated; selecting an explanation video currently displays a placeholder.
A note on standardization is important here. Like many other sign languages, NGT is characterized by large regional and social variation, with most of the variation occurring in its basic lexicon [32]. Despite this natural variation, the Dutch government made standardization a requirement for the official recognition of NGT1—a decision largely criticized by the Deaf community. This led to a project to standardize the NGT basic lexicon[32].2 In educational settings, including parental sign language courses, this standardized lexicon is typically used. This background is particularly relevant in the context of our prototype app, where some signs deviate from these standardized forms.
Mapping prototype features to design objectives
Having described the main features of the ZINinNGT prototype, we now link these features back to the three design objectives outlined in Sect. 3.1 to clarify the rationale behind the app’s design. As summarized in Table 3, each design objective is supported by specific prototype features.
Design objective | Prototype feature
Grammar-aware input | Grammar filterInformation buttonGrammar explanation videos
Perceptual control | Adjustable camera anglesAdjustable playback speedSubtitle options
Need-driven retrieval | Search barSearch filtersFavorites feature
The first objective, grammar-aware input, is supported by: (1) the grammar filter, which allows users to search for sentences containing specific grammatical constructions; (2) the information button, which links NGT sentences to their corresponding grammar explanation videos; and (3) the grammar explanation videos themselves, which offer explanations on NGT grammar and sentence formation.
The second objective, perceptual control, is addressed through the features that allow users to watch videos from multiple camera angles, adjust playback speed, and toggle subtitle options (on or off, sentence- or word-level focused). These features give parents control over how they receive NGT input, accommodating different learning preferences.
The third objective, need-driven retrieval, is supported by the search bar, search filters, and favorite marking option. Together, these features enable parents to efficiently find the videos they need, when they need them, aiming to make the app practical and easy to navigate.