Answer 1

First of all why you want to go with other if you have swift????
It doesn't make sense buddy.
C# or objective-c can be used but no one is better than Swift.

Answer 2

Objective C

Answer 3

Swift is the best language for it. Or Objective C. Because they are native.

You could also develop it with JavaScript if you want, but it is not the best way. How to do it:
https://google.com/search?q=javascript+build+ios+app

You can also combine Swift with JS, and Swift with Objective C. Objective C could be combined with C or C++. And then C with Assembler.

Using assembly code inside Objective c program (Xcode)
https://stackoverflow.com/q/25326307/9801830

Combining C or C++ and Assembler programs:
https://www.ibm.com/support/knowledgecenter/en/SSLTBW_2.3.0/com.ibm.zos.v2r3.cbcpx01/asmchap.htm

Answer 4

You could also use C# with Xamarin to develop native app both for iOs and Android!

Answer 5

hello

Answer 6

l am kearn man