Interacting with a speech interface to query a Question Answering (QA) system is becoming increasingly popular. Typically, QA systems rely on passage retrieval to select candidate contexts and reading comprehension to extract the final answer. While there has been some attention to improving the reading comprehension part of QA systems against errors that automatic speech recognition (ASR) models introduce, the passage retrieval part remains unexplored. However, such errors can affect the performance of passage retrieval, leading to inferior end-to-end performance. To address this gap, we augment two existing large-scale passage ranking and open domain QA datasets with synthetic ASR noise and study the robustness of lexical and dense retrievers against questions with ASR noise. Furthermore, we study the generalizability of data augmentation techniques across different domains; with each domain being a different language dialect or accent. Finally, we create a new dataset with questions voiced by human users and use their transcriptions to show that the retrieval performance can further degrade when dealing with natural ASR noise instead of synthetic ASR noise.

Dense retrieval is becoming one of the standard approaches for document and passage ranking. The dual-encoder architecture is widely adopted for scoring question-passage pairs due to its efficiency and high performance. Typically, dense retrieval models are evaluated on clean and curated datasets. However, when deployed in real-life applications, these models encounter noisy user-generated text. That said, the performance of state-of-the-art dense retrievers can substantially deteriorate when exposed to noisy text. In this work, we study the robustness of dense retrievers against typos in the user question. We observe a significant drop in the performance of the dual-encoder model when encountering typos and explore ways to improve its robustness by combining data augmentation with contrastive learning. Our experiments on two large-scale passage ranking and open-domain question answering datasets show that our proposed approach outperforms competing approaches. Additionally, we perform a thorough analysis on robustness. Finally, we provide insights on how different typos affect the robustness of embeddings differently and how our method alleviates the effect of some typos but not of others.

The tip of the tongue known-item retrieval (TOT-KIR) task involves the 'one-off' retrieval of an item for which a user cannot recall a precise identifier. The emergence of several online communities where users pose known-item queries to other users indicates the inability of existing search systems to answer such queries. Research in this domain is hampered by the lack of large, open or realistic datasets. Prior datasets relied on either annotation by crowd workers, which can be expensive and time-consuming, or generating synthetic queries, which can be unrealistic. Additionally, small datasets make the application of modern (neural) retrieval methods unviable, since they require a large number of data-points. In this paper, we collect the largest dataset yet with 15K query-item pairs in two domains, namely, Movies and Books, from an online community using heuristics, rendering expensive annotation unnecessary while ensuring that queries are realistic. We show that our data collection method is accurate by conducting a data study. We further demonstrate that methods like BM25 fall short of answering such queries, corroborating prior research. The size of the dataset makes neural methods feasible, which we show outperforms lexical baselines, indicating that neural/dense retrieval is superior for the TOT-KIR task.