Use of "parley" meaning to convert?

Solution 1:

The only verb sense of parley that I know or can find in dictionaries is intransitive: to parley with someone is to confer, hold talks, etc. with them. So to parley X into Y sounds wrong to me.

The usage I know which is much closer to your example is parlay, not parley. Merriam-Webster defines it as:

to use or develop (something) to get something else that has greater value

• He hoped to parlay his basketball skills into a college scholarship.
• She parlayed $5,000 and years of hard work into a multimillion-dollar company.

So the grammar of this absolutely fits your example. Your meaning doesn’t fit into M-W’s definition; but I would tend to agree with you that it’s now used a bit more broadly than their definition, generally as something closer to “to convert X into Y” or “to refashion/reimagine/reinterpret X as Y”.

Edit: The Corpus of Contemporary American English doesn’t reflect our feeling that it’s used more broadly: every instance of ‘parlay X into Y’ I checked fits the definition given by M-W. However, it does confirm that ‘parlay’ and ‘parley’ get mixed up fairly frequently — about 10% of the hits for each were in situations where, going by the dictionary definitions, it should have been the other.

Solution 2:

An old discussion by now, but I'll add. Then there is the word "parlay", which I've heard used to leverage (your "convert"?) an asset or advantage into something better. However, I think what I've (thought I've) heard is actually a misuse of the word parlay. The dictionary indicates that parlay means to use the winnings from a bet to make another bet and then win that bet.

Solution 3:

The borrowing of the French word parler (to talk) in English (spelled parley) comes from the medieval battlefields where "Frenchies" and "Gottons" had agreed to meet every now and then to settle various differences.

In order to express its readiness to stop shooting and start talking one of the belligerent would send some emissary to the other side who would shout "Parler !!!" and the negotiation could commence.

This is why among other meanings parley means:

• A truce or armistice in certain games; the place of truce
• An informal conference with an enemy, under a truce, for the discussion of terms, or the mutual arrangement of matters, as the exchange of prisoners; a discussion of terms.
• The beat of drum by which a conference with an enemy is desired.

See also parley-hill, in Scotland and Ireland, formerly, a mound, usually fortified, where the local disputes of neighbouring districts were debated and settled.

This is far from the suggested meaning in your quote. The only weak link with "parler" I can fiind is that of "to depict as".

Stargate depicts the Egyptian deities into villainous star-faring aliens.

So I'm not too sure how valid a usage this is.