Spontaneous Speech Assessment with SpeechSuper's API: Enhancing Language Testing Conversations are an essential part of our daily lives. In academic settings, speaking is necessary to express opinions and collaborate with peers. However, natural conversations are unscripted, making the evaluation of spontaneous speech a significant challenge. High-stakes English-level tests such as IELTS and TOEFL evaluate spontaneous speech based on multiple aspects, including vocabulary, grammar, pronunciation, fluency, and topic development. However, accurately and automatically assessing these aspects of spoken language presents a significant challenge. At SpeechSuper, we have taken on this challenge with the aim of developing precise and efficient evaluation methods. Drawing primarily from the evaluation rubrics used for IELTS speaking assessments, SpeechSuper's spontaneous speech assessment API will provide comprehensive scores for both overall performance and the 5 sub-dimensions ment