Final answer:
Caption service is largely provided by speech-to-text software, which is a specialized form of a speech recognition system, designed to transcribe spoken language into written text.
Step-by-step explanation:
Caption service is provided by a speech-to-text software using voice recognition technology. When someone speaks, the speech-to-text software, which is a type of speech recognition system, converts the spoken words into written text. This is particularly useful in creating subtitles for videos or providing real-time captioning for live events. Speech recognition has advanced significantly, allowing for highly accurate transcriptions. However, unlike translation services or video editing software, speech-to-text software focuses specifically on converting speech into text.