This is not well documented, which is an important issue since parsing is a difficult problem. Meaning is contextual.
If I say "this morning", what time does it give? Looking at the source, it assumes 8am. But what if I meant a different time?
If I say "this morning" at 1am, do I mean the morning of the day before, or the moorning which occurs later? Or do I mean the current time (which is still technically morning)?
How does it handle unknown words? If I say "this coming Friday" or vague phrases like "in a couple of days"?
Can I specify holidays? If so, words like "sabbath", "Easter", "Eid", or "Thanksgiving" are dependent on the religion, region, or country of the user.
There are no comparisons with Date::Manip, which has some similar functionality. (My own experience using Date::Manip in an application to give users flexibility in how they entered dates and times is that they had so many bizarre ways of specifying the time that it turned out to be easier for the developers and users to require a standard input format, which was eventually replaced with a drop-down menu for choosing the date and time.)
The idea behind it is nifty (in a toy kind of way), but it's strewn with pitfalls. From past experience with somehting similar, I'd not use this in a production environment.
And the obligatory namespace nitpick: should be in the Lingua::EN namespace, or at least indicate that it's English-language-specific.