When writing in English what is the benefit of loading `babel`, by `\usepackage[english]{babel}`, except for the possibility of setting it to use specific English dialects as described in babel: english, american, USenglish?

For example I know that `biblatex`, `csquotes` and `microtype` can work together with `babel` but their features seems to only make sense when writing in other languages than in English.

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you do not need babel, when you have a complete document in english. –  Herbert Sep 7 '11 at 7:57
@Herbert: You do if you are in the UK –  Joseph Wright Sep 7 '11 at 9:42
sure, but that is not the option english from default TeX –  Herbert Sep 7 '11 at 9:48
So it depends on whether your entire document is in English or in `english`. –  doncherry Sep 7 '11 at 9:58
@N.N.: I was just joking a bit on how Herbert and Joseph used different meanings of "English": Herbert was referring to the LaTeX option `english`, which means American English, and Joseph was referring to the language English, which in Joseph's case means British English. Essentially, there's a reason for using `babel` if you're writing in British English (Joseph's point), and (according to Herbert) you don't need it if you're writing in American English. –  doncherry Sep 7 '11 at 19:38

You should load babel if you're unsure about the default language. A system administrator in the UK may well have changed it to British English instead of US English (they have different hyphenation rules).

Assuming TeX Live is used (but also MiKTeX, I believe), lines such as

``````\usepackage[USenglish]{babel}
\usepackage[UKenglish]{babel}
``````

will guarantee that the requested hyphenation rules are used during typesetting. Another use for babel is for choosing a not directly supported set of hyphenation patterns; for example,

``````\usepackage{hyphsubst}
\HyphSubstLet{english}{usenglishmax}
\usepackage[english]{babel}
``````

will use the "maximal set" of US English hyphenation patterns (check your `language.dat` file for the exact string to use, `usenglishmax` is surely correct for TeX Live).

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Moreover, `USenglish` and `UKenglish` differ in the way quotation marks are used. For instance, `\enquote` of the `csquotes` package surrounds text with double quotation marks in case of `USenglish`, but with single quotation marks in case of `UKenglish`. –  mhp Sep 7 '11 at 9:09

Besides guaranteed proper hyphenation, if you load babel, you could access various useful shorthands related to hyphenation, such as provided by `ngerman`, even with `english` option:

• `\-` hyphenation with suppressed hyphenation before and after the break point
• `"-` hyphenation with enabled automatic hyphenation before and after the break point
• `""` for a hyphenation point without hyphen
• `"|` like `"-` but with disabling ligatures, adding a small space
• `-` (divis) for combined words
• `"~` for a dash where hyphenation is not allowed
• `"-` for a dash where hyphenation is allowed, also before and after

For example:

``````\usepackage[ngerman,english]{babel}
\useshorthands{"}
This has been asked and solved here: Adding `ngerman`s language shorthands to `english` as the main document language.