Comparison of a back-translation with the original text is sometimes used as a check on the accuracy of the original translation, much as the accuracy of a mathematical operation is sometimes checked by reversing the operation. But the results of such reverse-translation operations, while useful as approximate checks, are not always precisely reliable. Back-translation must in general be less accurate than back-calculation because linguistic symbols (words) are often ambiguous, whereas mathematical symbols are intentionally unequivocal.
What symbol set has a defining property of ambiguity?
linguistic

Input: Germans
The migration-period peoples who later coalesced into a "German" ethnicity were the Germanic tribes of the Saxons, Franci, Thuringii, Alamanni and Bavarii. These five tribes, sometimes with inclusion of the Frisians, are considered as the major groups to take part in the formation of the Germans. The varieties of the German language are still divided up into these groups. Linguists distinguish low Saxon, Franconian, Bavarian, Thuringian and Alemannic varieties in modern German. By the 9th century, the large tribes which lived on the territory of modern Germany had been united under the rule of the Frankish king Charlemagne, known in German as Karl der Groe. Much of what is now Eastern Germany became Slavonic-speaking (Sorbs and Veleti), after these areas were vacated by Germanic tribes (Vandals, Lombards, Burgundians and Suebi amongst others) which had migrated into the former areas of the Roman Empire.

how many tribes are credited with the creation of the modern day germans?
Output: five tribes

Input: Article: Developed at roughly the same time as the USB 3.1 specification, but distinct from it, the USB Type-C Specification 1.0 was finalized in August 2014 and defines a new small reversible-plug connector for USB devices. The Type-C plug connects to both hosts and devices, replacing various Type-A and Type-B connectors and cables with a standard meant to be future-proof, similar to Apple Lightning and Thunderbolt. The 24-pin double-sided connector provides four power/ground pairs, two differential pairs for USB 2.0 data bus (though only one pair is implemented in a Type-C cable), four pairs for high-speed data bus, two "sideband use" pins, and two configuration pins for cable orientation detection, dedicated biphase mark code (BMC) configuration data channel, and VCONN +5 V power for active cables. Type-A and Type-B adaptors and cables are required for older devices to plug into Type-C hosts. Adapters and cables with a Type-C receptacle are not allowed.[citation needed]

Now answer this question: What connector provides four power/ground pairs?

Output: The 24-pin double-sided connector

Article: The chapter house was built concurrently with the east parts of the abbey under Henry III, between about 1245 and 1253. It was restored by Sir George Gilbert Scott in 1872. The entrance is approached from the east cloister walk and includes a double doorway with a large tympanum above.

Question: Under whom was the chapter house built?
Ans: Henry III

Here is a question about this article: In his Harvard "Lectures on Pragmatism" (1903), Peirce enumerated what he called the "three cotary propositions of pragmatism" (L: cos, cotis whetstone), saying that they "put the edge on the maxim of pragmatism". First among these he listed the peripatetic-thomist observation mentioned above, but he further observed that this link between sensory perception and intellectual conception is a two-way street. That is, it can be taken to say that whatever we find in the intellect is also incipiently in the senses. Hence, if theories are theory-laden then so are the senses, and perception itself can be seen as a species of abductive inference, its difference being that it is beyond control and hence beyond critique in a word, incorrigible. This in no way conflicts with the fallibility and revisability of scientific concepts, since it is only the immediate percept in its unique individuality or "thisness" what the Scholastics called its haecceity that stands beyond control and correction. Scientific concepts, on the other hand, are general in nature, and transient sensations do in another sense find correction within them. This notion of perception as abduction has received periodic revivals in artificial intelligence and cognitive science research, most recently for instance with the work of Irvin Rock on indirect perception.
What is the answer to this question: When was 'Lectures on Pragmatism' published?
****
So... 1903

Article: In January 1790, Burke read Dr. Richard Price's sermon of 4 November 1789 entitled, A Discourse on the Love of our Country, to the Revolution Society. That society had been founded to commemorate the Glorious Revolution of 1688. In this sermon Price espoused the philosophy of universal "Rights of Men". Price argued that love of our country "does not imply any conviction of the superior value of it to other countries, or any particular preference of its laws and constitution of government". Instead, Price asserted that Englishmen should see themselves "more as citizens of the world than as members of any particular community".

Question: When did Richard Price give a sermon to the Revolution Society?
Ans:
4 November 1789