I rewrote the helpers.parse function to achieve a few things:
Allow easier definition and modification of time keywords
Support multiple languages
Support time strings without a leading digit (eg 'day' is the same as '1 day')
The framework for defining extra languages is a dict of regexes for matching the various week, day, hour, minute, and second bits. I have made definitions for English, and a hacked together (very likely incorrect) definition for German for testing. The definitions should probably be moved to a separate file, but I was unsure of your preferences here.