Introduction

The significance of early language development is well described in the child language literature. Research indicates that while early language skills are important in their own right, they also support a child’s social-emotional and cognitive development, and predict future language development [1–3]. Deaf and hard of hearing (DHH) children who receive early sign language input follow the same language milestones as hearing children acquiring spoken language in the same order and at a comparable rate [4–6]. However, 90–95% of DHH children are born to hearing parents [7], who generally do not know a sign language. In fact, for many of these parents, the birth of their DHH child is the first experience they have with sign language and the Deaf community [8]. As a result, DHH children often experience a delay in acquiring their first language, which can have life-long consequences for the child’s linguistic, social-emotional and cognitive development [1, 2, 9–11].

To prevent language deprivation, it is crucial that hearing parents of DHH children learn a sign language as early as possible. Yet, learning a sign language presents many challenges for parents. Relatively few courses and resources exist, and those that are available are generally designed for adult learners in general rather than specifically for parents [12]. This distinction matters: while other learners typically focus on communication with adults, parents need resources that prepare them for interaction with a young child, requiring different vocabulary, sentence constructions, and communicative situations.

Moreover, existing sign language materials (such as books, YouTube videos, and apps) are often overly focused on vocabulary learning rather than on sentence formation. Parents often rely on web-based dictionaries for sign language learning [13], and even during formal, offline courses, the lack of instruction on language structure is a common frustration among parents [14–16]. Similarly, Oyserman and de Geus [17] found that while Dutch parents had learned various signs during their Dutch Sign Language (Nederlandse Gebarentaal, NGT) courses, they barely learned the syntactical, semantic, and morphological features of NGT.

Further focusing on the Dutch context, in a previous publication [16], we examined hearing parents’ experiences learning NGT through semi-structured interviews with 21 parents and six NGT teachers. Parents reported that existing NGT courses offered too little—and too late—grammar instruction, that courses often misaligned with their children’s age and that course materials were often outdated. When discussing self-study resources, parents valued materials that were fun and could be used together with their child. However, they also noted that resources were often difficult to access (e.g., requiring lengthy login procedures or being restricted to computer use rather than mobile devices) and limited in scope. NGT teachers largely echoed these concerns, pointing to an overemphasis on vocabulary, outdated materials, and a lack of content specifically designed for parents.

Together, this context underscores the need for up-to-date tools that are easily accessible, parent-focused, and supportive of sentence-level learning. Therefore, we have developed ZINinNGT,¹ an NGT learning app specifically designed for hearing parents of DHH children. The app is intended to complement offline NGT courses for parents of DHH children aged one to five years. By providing example sentences containing core vocabulary and grammatical constructions, ZINinNGT aims to strengthen parents’ practical NGT skills and thereby indirectly support DHH children’s access to NGT. Furthermore, because all sentences are typical of parent–child conversations and thus directly applicable in discourse, ZINinNGT seeks to contribute to the improvement of parent–child interaction.

Within this paper, we describe the development and evaluation of the ZINinNGT prototype. The key contributions of this paper are the following:We present and evaluate a set of interaction techniques designed to support parents in learning full sentences in NGT. These include options such as viewing from multiple camera angles, adjusting playback speed, toggling between sentence-level and sign-for-sign subtitles, and searching by grammatical features.We distill eight design principles for parent-facing sign language learning tools: grammar-aware input, perceptual control (adjustable camera angles, playback speed, subtitle options), need-driven retrieval (find what you need, when you need it), holistic design (integrating sentences, lexicon, and practice components), design for learner motivation (implementing gamification elements), visual-first (low text), variant-aware (supporting regional and standard variants), and joint parent–child use.We provide empirical evidence from a user study with parents and teachers, linking specific breakdowns (e.g., text-heavy interface, not child-friendly) to concrete UI changes and improved task performance.

The paper is structured as follows. We begin with describing related work in the next section. Section 3 presents the initial design objectives of ZINinNGT and describes the design of the prototype. Section 4 outlines the methodology of our user study, and Sect. 5 presents the results. Finally, Sects. 6 and 7 provide the discussion and conclusion.

Footnotes

1. The name ZINinNGT is a word play, meaning both “Sentence in NGT” and “In the mood for NGT” in Dutch. ↩