Which language i must learn to develop an app?

Question

i want to build apps. i need to know from which language i need to start . and how many languages are necessary for me to learn to be a professional app builder.

Answer 1

For android apps, learn Java.
For iOs apps, swift
For cross-platform apps, learn JavaScript (react native, ionic, angular+nativescript)

Answer 2

In the end, you'll realize language(s) doesn't matter the most but logic of codes does...