  Utilizing Visualization-oriented Natural Language Interfaces (V-NLI) as a
complementary input modality to direct manipulation for visual analytics can
provide an engaging user experience. It enables users to focus on their tasks
rather than having to worry about how to operate visualization tools on the
interface. In the past two decades, leveraging advanced natural language
processing technologies, numerous V-NLI systems have been developed in academic
research and commercial software, especially in recent years. In this article,
we conduct a comprehensive review of the existing V-NLIs. In order to classify
each paper, we develop categorical dimensions based on a classic information
visualization pipeline with the extension of a V-NLI layer. The following seven
stages are used: query interpretation, data transformation, visual mapping,
view transformation, human interaction, dialogue management, and presentation.
Finally, we also shed light on several promising directions for future work in
the V-NLI community.
