system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do programmers use multiple languages to build a product? How do they connect it together?
gpt
Imagine you are cooking something, you usually have a recipe that you need to follow, each steps builds on the previous one. For instance, if you wanna make fries you:  


1. Find a potato (tool: fridge)
2. Wash the potato (tool: sink)
3. Peel the potato (tool: knife, peeler)
4. Slice the potato (tool: knife)
5. Fry (tool: stove, pan)
6. Serve (tool: plate, table)

Each tool can be considered a different programming language, and each step can be considered a "layer" of your application.

Each layer has an expected format for input and output (e.g. to peel the potato you receive a washed potato, and your output is a peeled potato). In practice, different languages pass input and output to each other using your computer memory (RAM) or storage space; they create files and pieces or information that follow certain "structure", such that the next layer can pick it up from there.