As a terrible human being, I tested Chinese-to-English translations on f-word-based profanity on the demo page (https://demo-pnmt.systran.net/production). The results were arguably not as good as Google Translate, which can recognize the colloquial form 操[^1] but not the more orthodox 肏. PNMT's results were great in another way as they form more fluent English.

  [^1]: Everyone hijacked the character.

On the other hand, OpenNMT appears able to translate the "f* you!" sentence to "你妈！" in Chinese, a form of "操你妈" with the F word not spoken but implied. The single-f-word sentence generates amusing variations when used with different punctuations, although many ("...", "?", "!", "") fail by reducing the sentence to a normal call for one's own mother.

These experiments make me curious about what kind of corpora the system was trained on.

* * *

The test sentences used were:

    操你十八辈子祖宗！[^2]
    操你十八辈祖宗！
    操你妈！
  [^2]: This one is technically wrong.

For the orthodox version, replace all instances of 操 with 肏.

As an additional experiment, I tested some variations of "mother" profanities without "操":

    1. 你妈！
    2. 他妈的！
    3. 他妈的。

Between #2 and #3, PNMT appears more sensitive to punctuations than human do. #1 is only included as a round-trip validation.

Edit: (#1) ... and is not supposed to be translated back into profanity due to high false positive rate.