When Treat Punctuation as separate tokens is selected, punctuation is handled in a similar way to the Google Ngram Viewer. Punctuation at the beginning and end of tokens is treated as separate tokens. Word-internal apostrophes divide a word into two components. For example, Maria said "I'm tired." is divided into eight tokens: Maria said " I 'm tired . ".
Open Source
The source code is available for free under a Creative Commons Attribution BY-SA license. This license enables you to share, copy and distribute the code. You can also remix it.
The code can be downloaded from our github repository.