Merge pull request #858 from UniversalDependencies/nschneid-typo-def

Typo definition

_u-feat/Typo.md

@@ -12,13 +12,31 @@ udver: '2'
 </tr>
 </table>
 
-Indicates bad spelling, grammatical error etc. This also includes mistakenly interrupted words that are connected using the [goeswith]() relation.
-While the annotation of morphological features is optional, if the treebank does have features, then [Typo]()`=Yes` must be used with the `goeswith` head.
+Indicates an erroneous or typographically unexpected word form. 
+
+Most unexpected spellings are typographical errors (inadvertent on the part of the author). Also unexpected: creatively using special characters or spaces for visual effect; or unusual character encoding.
+For transcribed speech, no distinction is made between the original speaker and the transcriber, so a mispronunciation like _shilly_ for _silly_ is also treated like a typo.
+This feature can also encompass clear errors in word choice, such as learner errors and dysfluencies (e.g. _lesser_ where _fewer_ is appropriate, or _eats_ instead of _eat_).
+
+Note that "typographically unexpected" is interpreted in the context of the genre. Abbreviations or popular informal spellings are not necessarily unexpected. See [Abbr]().
+
+Superfluous word-internal spaces are addressed using the [goeswith]() relation to connect parts of the word.
+[Typo]()`=Yes` should be used with the `goeswith` head (and this is enforced by validation for treebanks that use features).
 
 The correct spelling can be indicated in the MISC column with the `CorrectForm` feature,
 as discussed in the [page on typos](https://universaldependencies.org/u/overview/typos.html).
 
-Intentionally nonstandard spellings are not considered typos. They should be marked as abbreviations ([Abbr]()) or expressive spellings ([Style]()`=Expr`).
+**Capitalization, etc.:**
+Cases where an unexpected form of a letter is used within a word—e.g., unexpected capitalization choices—should be handled on a language- and treebank-specific basis. In a social media treebank, for example, it may not be practical to flag all nonstandard capitalization choices as [Typo]()=`Yes` given the wide variability of capitalization in unedited writing.
+
+**Stylistic choices:**
+[Typo]()=`Yes` is intended for specifically orthographic unexpectedness, not unexpected word variants in general. If the author is taken to be signaling an intentionally modified pronunciation of a word, inventing a new word, or making a pun, that is not Typo if the unexpectedness is reflected phonologically. 
+The optional [Style]() feature may be useful in such cases.
+Deliberate, well-established conventions of altering the written forms of words, e.g. censoring profanity with nonalphabetic symbols, should also be considered expressive stylistic choices rather than typographical unexpectedness.
+
+**Extra words:**
+For extra or missing words, see the [policy on errors](https://universaldependencies.org/u/overview/typos.html).
+A valid word that is superfluous in the sentence and attached as [reparandum]() does not receive [Typo]()`=Yes`.
 
 ### <a name="Yes">`Yes`</a>: it is typo