Sight translation involves reading a written text in one language silently, and simultaneously speaking the content aloud in another language.
For example, a legal firm may ask a Japanese to English translator to sight translate parts of Japanese documents, speaking the content aloud in English so they can identify what the documents are and whether they are relevant to a case and need to be translated in full.
Sight translation is highly skilled and requires a high degree of fluency in at least two languages, as well as knowledge of the subject matter of the documents being sight translated (e.g. experience of the legal system or a technical background).