I'm trying to understand how a certain stock fluctuates, I noticed periods recently when the Bid/Ask volume looks like 50,000/500 give or take. What does this mean in human language in terms of interest for that particular stock?
The size of the market refers to how many shares are being bid for or offered to sell at the respective bid and ask prices.
In this case it means that 50,000 shares are bidding to buy stock at the bid and 500 shares are being offered for sale at the ask.
Noet that there are algorithmic orders in use today. For example, an iceberg order is a type of hidden order that only displays a portion of the order (like the tip of an iceberg that is seen outside of the water). When that 500 shares is sold, another 500 will display at that price and so on until the complete order is filled or price changes.
So while your quote of 50,000 x 500 implies buying pressure, it doesn't necessarily mean that only a single 500 shares order exists at the ask price.