CLDR-19290 Update plural-rules.md (#5432)

Author: macchiati

docs/site/index/cldr-spec/plural-rules.md

@@ -44,18 +44,71 @@ with an extra one for fractions. For example:
 
 ## Determining Plural Categories
 
-The CLDR plural categories do not necessarily match the traditional grammatical categories. Instead, the categories are determined by changes required in a phrase or sentence if a numeric placeholder changes value. 
+The CLDR plural categories do not necessarily match the traditional grammatical categories.
+Instead, the categories are determined by changes required in a phrase or sentence if a numeric placeholder changes value.
+That numeric placeholder is represented by {0}, and will be replaced by a series of digits.
 
 ### Minimal pairs
 
-The categories are verified by looking a minimal pairs: where a change in numeric value (expressed in digits) forces a change in the other words. For example, the following is a minimal pair for English, establishing a difference in category between "1" and "2".
+For both plurals (aka cardinals) and ordinals, CLDR requires what are called _minimal pairs_, both to justify and verify the categories, and to supply examples for vetters. 
+A set of minimal pairs provides one example per category, where a change in numeric value (expressed in digits) forces a change in the other words.
+Although the term used is _minimal pairs_, this refers to pairwise differences; the set of minimal pairs for a given language might be as many as 6 examples.
+There are three general types of appoaches to this: *noun changes*, *verb changes*, and *pronoun changes*.
+
+When creating minimal pairs, often vetters try noun changes, and don't find any in their language. 
+They then give up and say that there are no minimal pairs for their languages.
+When the software requires them to provide minimal pairs, they then provide bad examples.
+The following examples illustrate the approaches, and the subsequent sections provide details.
+
+#### Noun Changes
+Do nouns change if an associated number changes?
+
+| Category | Resolved String | Minimal Pair Template |
+|---|---|---|
+| one | 1 day | {0} day |
+| other | 2 day<b>s</b> | {0} day<b>s</b> |
+
+When trying to create minimal pairs, check different nouns in your language.
+If your language has gender or grammatical cases for nouns, try phrases with nouns of different genders or different cases. 
+For example, in some languages neuter nouns might not change with numbers, but masculine nouns might; or phases where the noun is genitive might. 
+Remember that there must be no semantic differences in the phrases for each category *other than those required by a change in the number*.
+Note also that the noun must be one that works in your language: it does *not* have to match the English noun.
+More details are below.
+
+#### Verb Changes
+In some languages, no nouns change with numbers: they are all like the English noun "sheep".
+
+| Category | Resolved String | Minimal Pair Template |
+|---|---|---|
+| one | 1 sheep | {0} sheep |
+| other | 2 sheep | {0} sheep |
+
+For those languages, _verb changes_ may be needed to demonstrate changes between categories.
+
+| Category | Resolved String | Minimal Pair Template |
+|---|---|---|
+| one | 1 sheep _is_ here | {0} sheep _is_ here |
+| other | 2 sheep _are_ here | {0} sheep _are_ here |
+
+#### Pronoun Changes
+In some languages, neither nouns nor verbs ever change with numbers: they are all like "sheep" and "will be".
 
 | Category | Resolved String | Minimal Pair Template |
 |---|---|---|
-| one | 1 day | {NUMBER} day |
-| other | 2 day s | {NUMBER}  day s |
+| one | 1 sheep will be here | {0} sheep will be here |
+| other | 2 sheep will be here | {0} sheep will be here |
+
+For those languages, _pronoun reference_ changes may be needed to demonstrate changes between categories, where a pronoun references the noun associated with the number.
+
+| Category | Resolved String | Minimal Pair Template |
+|---|---|---|
+| one | 1 sheep will be here; will you see _it_? | {0} sheep will be here; will you see _it_? |
+| other | 2 sheep will be here; will you see _them_? | {0} sheep will be here; will you see _them_? |
+
+#### Other Changes
+In some languages, other grammatical constructions may be needed to verify the categories.
 
-Warning for Vetters
+### Warning for Vetters
 
 The Category (Code) values indicate a certain range of numbers that differ between languages. To see the meaning of each Code value for your language see [Language Plural Rules](https://www.unicode.org/cldr/charts/latest/supplemental/language_plural_rules.html) chart.