Custom vocabulary is a pivotal feature in speech-to-text (STT) systems that significantly enhances transcription accuracy by allowing users to add specific words and phrases, such as brand names, technical acronyms, and regional slang, to the recognition list. This feature is especially valuable in call centers and customer service platforms where transcription errors can lead to disrupted workflows and poor customer experiences. By integrating custom vocabulary, STT engines can more accurately handle unique pronunciations and industry-specific language, thus improving data quality for analytics and automation. Companies like Gladia offer sophisticated API solutions that make implementing custom vocabulary easy and effective, enabling call center as a service (CCaaS) and voice platform providers to deliver more precise transcriptions and enhance agent productivity. This approach not only supports improved customer experiences but also empowers users to define terms critical to their business, resulting in richer insights and more reliable automated processes.