How are languages deciphered?

Question

How do archaeologists, cryptoanalysts and linguists decipher extinct languages? Has there been a case in history where this was successfully accomplished, without the means of something like the Rosetta stone or people that still speak a similar variant of the language in question?

Obviously you start out by collecting statistics. How often do characters appear, how often do certain characters appear together, etc. But what do you then do with those statistics? How does it help knowing that A E I O U are vowels, or that u almost always follows q and that h frequently follows t in English?

If you were to discover English, without knowing anything about it (except for maybe that it is an alphabetical language), or any related languages, how would you go about deciphering it? To simplify things let's assume a fairly simplified version of English with only abstract concepts like squares or triangles. If you had books full of sentences like "A square consists of two triangles", "A triangle consists of three lines intersecting with each other", etc. how could one extract the meaning of those sentences without prior knowledge of the language?

Answer 1

You should read Peter T. Daniels' 1996 article "Methods of decipherment" in an excellent book, The world's writing systems, eds. Daniels and Bright. New York: Oxford University Press. He has a really nice table, "Typology of decipherment" (adapted from Gelb 1973, 1975):

• Type O: (e.g., Punic texts written in Greek letters, Indian names in Chinese Buddhist compositions)
• Type IA: (e.g. Phoenician, Ugaritic)
• Type IB: familiar languages in unknown scripts (e.g., Linear B, Maya glyphs)
• Type II: codes and ciphers (cryptanalysis); pronounceable but unintelligible languages (e.g., Sumerian, Elamite, Hittite)
• Type III: (e.g., Mesopotamian cuneiform)

In the above-mentioned article, you can also read about steps in decipherment (cataloging, distributional analysis etc.)

The number of different characters is also important:

about 30 => abjad (alphabet);

about 100 => abugida (syllabry);

about 300 => logosyllabry (logography)

Re your last question, at first, most, if not all, languages are in contact with each other, i.e. there are borrowings. Secondly, there are extra-linguistic cues, e.g. a place where your text was found (thus, you may expect words for certain concepts, like certain types of trees or animals). People who spoke that unknown language should have contacts with other civilizations, thus, you may find certain proper names or concepts mentioned in an already known language.

In your example, there might be drawings of triangles and squares etc. All that might help make educated guesses and it could be a good start.

Indeed, there are some (still) undeciphered languages, because either there isn't enough material to (credibly) decipher them or nothing is known about their linguistic affinity.

Answer 2

The short answer is that, in the scenario you give, It's currently not possible.

All of the decipherments to date have depended on some secondary reference, be it a version of the text in a known language, some illustrations, or some other clues as to the content of the text.

In the example you give, just plain text describing abstract geometric figures, would need diagrams included to be deciphered.