The Collaborative International Dictionary of English v.0.48:

Interpretable \In*ter"pret*a*ble\, a. [L. interpretabilis: cf.
   F. interpr[^e]table.]
   Admitting of interpretation; capable of being interpreted or
   explained.
   [1913 Webster]

WordNet (r) 3.0 (2006):

interpretable
    adj 1: capable of being understood; "explainable phenomena"
           [syn: explainable, interpretable]

Moby Thesaurus II by Grady Ward, 1.0:

41 Moby Thesaurus words for "interpretable":
   Englishable, accountable, allegorical, associational,
   connotational, connotative, construable, definable, denotational,
   denotative, describable, explainable, explicable, expressive,
   extended, extensional, figurative, full of meaning, full of point,
   full of substance, indicative, intelligible, intensional, meaning,
   meaningful, meaty, metaphorical, pithy, pointed, pregnant,
   readable, referential, renderable, sententious, significant,
   significative, substantial, suggestive, symbolic, transferred,
   translatable