Please allow me to import this post of mine from another SE site:
I'll come back and revise it with relevant examples from this site after researching...
Hey Russian enthusiasts! I'd just like to revisit an old issue that comes up sooner or later in every young Stack Exchange site: Plural tags should be the lead tag in a set of tag synonyms.
Rather than be taken too literally and have this rule of thumb mechanistically over-applied, let me qualify that English is quirky and sometimes the singular is better.
Some nouns refer to "things" and some refer to "stuff" and some work for both.
If something is "stuff" then the singular tag is probably better even if the word can be plural too. For instance
grammar is a better tag than
Some special phenomena are best expressed by singulars, especially grammar and linguistics terms sometimes. A good test is to try in a question of the form "When should we use (the) XXX?" For instance "When should we use the soft-sign" is better than "When should we use the soft-signs?".
If something is an abstract concept then the singular tag is better. For instance
etiquette is better than
If in doubt try using the tag you are thinking of in an English sentence of the form "I like ABC". For instance "I like backpacks" is better than "I like backpack" but "I like beer" is better than "I like beers".
Another test is to imagine you're writing an article or paper on the topic. For instance
prepositions is better than
grammar is better than
The above two tests also apply to verbs. If your question is about some topic naturally expressed by a verb, use these tests to find a way to express it with a noun instead. For instance
pronunciation is better than