  It is not uncommon for Internet users to have to produce a text in a foreign
language they have very little knowledge of and are unable to verify the
translation quality. We call the task "outbound translation" and explore it by
introducing an open-source modular system Ptakop\v{e}t. Its main purpose is to
inspect human interaction with MT systems enhanced with additional subsystems,
such as backward translation and quality estimation. We follow up with an
experiment on (Czech) human annotators tasked to produce questions in a
language they do not speak (German), with the help of Ptakop\v{e}t. We focus on
three real-world use cases (communication with IT support, describing
administrative issues and asking encyclopedic questions) from which we gain
insight into different strategies users take when faced with outbound
translation tasks. Round trip translation is known to be unreliable for
evaluating MT systems but our experimental evaluation documents that it works
very well for users, at least on MT systems of mid-range quality.
