Another book you may enjoy in this vein is Umberto Eco's The Search for the Perfect Language — https://www.amazon.com/Search-Perfect-Language-Making-Europe....

I admire anyone who sets out to invent a language... but of course, there are two categories: the "true" invented languages, which are intended to sound as "foreign" as possible to human ears (Klingon, Tolkien's languages, ...) and languages like Volapük and Esperanto, that were based on common roots of various languages in order to sound more familiar (at least to people who already speak a European language).

If you read German I highly recommend "Die Bienen und das Unsichtbare" by Clemens Setz.

I strongly second this recommendation. I loved this book.

Written by the author of this article (Arika Okrent).