What is the origin of the idiom "put in a word for someone" and when to use it?

The origin of the idiom "put in a word for someone" can be traced back to the idea of using words as a form of influence or recommendation. It likely emerged from the practice of people using their spoken or written words to vouch for someone's character or abilities. In social and professional contexts, individuals would verbally advocate for others, emphasizing their qualifications or suitability for a particular role or opportunity. This phrase is typically used in various contexts and occasions where one person seeks to support or assist another person by recommending them to their acquaintances.