You can not compare iOS and Android Apps. They are written in different programming languages, they contain different libraries and they are executed on totally different runtime platforms.
Furthermore an iOS is a fat binary containing one app multiple times - currently usually two times: One 32bit binary and one 64bit binary.
On Android side only native libraries are contained for each platform. For WhatsApp you mentioned it looks a bit different: There are different APK files, one for each platform. The APK files from ApkPure only contain the libraries for ARMv7a (ARM 32 bit). Their size is about 4MB - this makes the APK again smaller.
Conclusion: Multiple languages are most likely not the reason for app binaries to get large.
Regarding the supported languages the iTunes link clearly states the different supported languages.
For Android the info is not available on a website. You have to download the app and the use the
aapt tool from Android SDK:
aapt dump badging "WhatsApp Messenger_v2.18.122_apkpure.com.apk" | find "locales"
aapt dump badging "WhatsApp Messenger_v2.18.122_apkpure.com.apk" | grep "locales"