The best suited for human readability is probably the
Manchester Syntax:
http://ceur-ws.org/Vol-216/submission_9.pdfAfter that, I would go to
Notation3 (n3) and its subset
Turtle (ttl).
Turtle was published as a W3C Recommendation in early 2014:
https://www.w3.org/TR/turtle/Then you have
N-Triples (nt), a subset of Turtle (and therefore Notation3):
https://www.w3.org/TR/n-triples/N-Triples was also published as a W3C Recommendation in early 2014, alongside Turtle, and is the only one from the list above supported by Owlready2.
Both Notation3 and Turtle are readable by RDFLib, which you can use as an interface to parse ontologies into one of the formats supported by Owlready2.
Note that Notation3 can also be used to express rules (
Notation3 Logic), which can be used in reasoners like
CWM or
EYE.