Solecisms are both faux pas and grammatical mistakes. I'm really just saving this here for later, but The Economist has provided a list of common solecisms, presumably for the use of their excellent writers.
Here's one that's troubling for many writers of any form of English:
Which informs, that defines. This is the house that Jack built. But This house, which Jack built, is now falling down. Americans tend to be fussy about making a distinction between which and that. Good writers of British English are less fastidious. (“We have left undone those things which we ought to have done.”)
Fussy and fastidious, are we? I would have thought that was primarily a British trait. Still, the general rule in American usage is: that introduces a restrictive clause, while which introduces a nonrestrictive one. Full stop, which disallows their third example above.
Bryan Garner's Modern American Usage says this:
Hence, three guidelines. First, if you cannot omit the clause without changing the basic meaning, the clause is restrictive; use that without a comma. Second, if you can omit the clause without changing the basic meaning, the clause is nonrestrictive; use a comma plus which. Third, if you ever find yourself using a which that doesn't follow a comma (or a preposition), it probably needs to be a that.
What? Ah. Well, a clause is er, um. Look it up. It's a part of a sentence. A restrictive clause (as the Economist example points out) defines: the house that Jack built, not any other house. Nonrestrictive clauses inform, but could be omitted: This house, which Jack built, is now falling down could be This house is now falling down.
The problem with rules like these -- about which Garner cites grammarians definig back to 1860 -- is that as time passes, the graceful and useful distinction fades away, leaving no real distinction. This is as it should be, as language evolves and refuses some rules, but careful writers will continue to write for each other and a dwindling population of grateful readers.
