## 2 Materials and Methods  
The experiment was designed and developed using a sequential process in which we connected two assessments with different objectives and strategies, following the Xassess evaluation methodology [32]. We selected Xassess because it is a methodology for user needs and product assessments by multidisciplinary teams (as is the author's team), which offers several advantages: it easily adapts to the context, considers the assessment from the initial stages of the project, merges qualitative and quantitative approaches, and includes the user's vision from the beginning of the project. Xassess may involve three evaluation strategies: complementation (each product dimension is evaluated with one qualitative or quantitative technique), triangulation (each dimension is evaluated with two or more parallel techniques), and combination (each dimension is evaluated with two or more successive techniques). In this study, we followed the combination strategy with a final triangulation, as shown in Table 1.  
The first experiment enabled us to identify the main terminology used to manage maps on a web browser. Using the mouse, we are accustomed to zooming in or panning around the map in any direction. However, would we verbally instruct the browser to move the map \"to the right\" or \"to the East\"? Initially, we developed a study to identify the common words used to command a map in a browser. To that end, we conducted an online video-based survey with a multimedia questionnaire including mainly open questions, which were answered by 137 Spanish speakers aged 16-75 (Figure 2). The survey was distributed through mailing lists to many users, to gain a diverse sample. For example, although this study was developed in Spain, effort was made to reach other Spanish-speaking countries and sample Latin Americans (we obtained answers from Argentina 1.48%, Colombia 4.44%, Chile 1.48%, Cuba 1.48%, Guatem 1.48%, Mexico 2.22%, Peru 2.22%, the Dominican Republic 1.48%, and Spain 83.70%). The data are included with this paper in the Supplementary Materials (File S1). \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Step** & **Objective** & **Method** & **No. of Samples** \(n\) \\ \hline
1 & Identify terminological corpus. & Survey. & 137 \\ \hline
2 & Identify the chain of commands. & Wizard of Oz. & 10 \\  & User behavior and acceptance. & Interviews. & 3 \\ \hline  & Expert testing before user test. & Cognitive walkthrough + & \\  & Validate prototype functionality. & heuristics. & 3 \\ \cline{2-4}
3 & Create technology for VUI as a first approach.Validate results obtained in previous steps. & Prototype + user testing. & 8 \\ \hline
4 & Emerging issues (transversal). & Triangulation of methods. & \\ \hline  & & & 158 (total) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Methods, dimensions, and objectives of our methodology. Based on the survey results and subsequent conclusions, the second experiment aimed to determine how users employ those common terms by creating a chain of commands to yield useful responses from the system. Once the system could understand the main commands, the next challenge was to connect them to provide similar end-user functionality as that obtainable with a mouse and keyboard. For instance, when traveling to Sri Lanka on business, one would probably like to see the tourist sites. How can we develop this particular functionality for the system? Other concerns include how the user will react, how the user will chain commands, and what happens if the system fails to respond properly (the noun Sri Lanka is difficult to pronounce for Spanish people). In the latter part of the second experiment, we carried out a qualitative assessment, using the Wizard of Oz method, with 10 people aged 22-56. The user profile varied in terms of gender, age, and familiarity with technology and GIS systems, to reflect the profiles of the survey population. Due to the in-person nature of the experiment, all of the users were Spanish nationals.