You can pick up the language by context of how words are used. No harder than keeping up with new language firehose put out through social media.

As extra reach, it's useful to have a printed copy of the dictionary from before the internet. This is the last anchor-point of widest accepted definition of language before it was easy to redefine what words mean from one week to the next. Printed copy provides a Rosetta stone for earlier texts not influenced by modern conceptions of what would be useful running afoul of what is.