Which language should I learn for arduino

Answer 1

https://code.sololearn.com/WQm0BRcm7hE5/?ref=app

See this this may help you

Answer 2

C language

You need to learn C language. Arduino is a mix of C/C++ along with more specific Arduino libraries. You can start learning C/C++ from scratch, get good basics, and then switch to Arduino, but you can also learn C language directly on the Arduino.