You could always pick one language to be an "expert" in and just study up on the book learning for that language for your interviews. I've shipped products in a

You could always pick one language to be an "expert" in and just study up on the book learning for that language for your interviews. I've shipped products in a dozen languages myself, but for an Android interview I'll only claim to be expert in Java and Kotlin, for iOS I'll only claim to know Objective-C and Swift, and for server I only claim to know Java and Go - even though I've shipped PhoneGap and React Native JS mobile apps, JS Node servers for startups that got funded, Amazon lambda functions triggered from Unity, etc.. Just not up to speed on the book learning/pop quiz/mind teaser type questions I'd get for those.