If you're not manually tagging conversations to track topics, what do you use to do that for you?

I'd like to know, for example, how many members wrote in about green frogs last month.

The next week, if there's a rise in conversations about red turtles, I want to be alerted that this is becoming a trending topic from members reaching out. I don't want to rely on our CS team to notice the trend, because with the sheer volume of conversations we're handling, it shouldn't (and can't) be up to human eyes to spot these trends.

Thank you SO much for any help or suggestions!