fraglingual

The fragmented or partial knowledge of a second language spoken with such impeccable pronunciation that it is indistinguishable from a native speaker of that second language; applicable only if the speaker can recite no more than five full sentences.

After Alex responded to the French tourists' initial inquiry using flawless French she was unable to answer or understand any follow-up questions due to her only being fraglingual; the tourists thought this to be a cruel joke and began cursing at her; Alex had no idea what they were saying.